[Streak 5 Q&A, Help & Troubleshooting] Spectre51:
I dug a little deeper into this and pulled the logs from logcat when opening and connecting to the market. What it looks like is happening to me, being on AT&T, is that it is disconnecting me from the default ATT US apn and reconnecting me to the ATT MMS apn to use the market. The network error or loss of data connectivity is due to the time it takes for one apn to disconnect and the second to connect and get active. You can look at the logs yourself and see. I encourage everyone else to try this on theirs and see what they find.

05-02 15:09:03.709: INFO/ActivityManager(149): Starting activity: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=com.android.vending/.AssetBrowserActivity }
05-02 15:09:03.829: INFO/ActivityManager(149): Start proc com.android.vending for activity com.android.vending/.AssetBrowserActivity: pid=10462 uid=10067 gids={1015, 3003}
05-02 15:09:03.979: INFO/ActivityThread(10462): Publishing provider com.android.vending.SuggestionsProvider: com.android.vending.SuggestionsProvider
05-02 15:09:03.999: DEBUG/vending(10462): [1] VendingApplication.onCreate(): Resetting ServiceLocator from app
05-02 15:09:04.029: INFO/Database(10462): SQLiteDatabase open path: /data/data/com.android.vending/databases/assets14.db
05-02 15:09:04.169: INFO/Database(10462): SQLiteDatabase open path: /data/data/com.android.vending/databases/billing4.db
05-02 15:09:04.489: INFO/Database(262): SQLiteDatabase open path: /data/data/com.google.android.gsf/databases/gls.db
05-02 15:09:04.499: DEBUG/GoogleLoginService(262): onBind: Intent { act=android.accounts.AccountAuthenticator cmp=com.google.android.gsf/.loginservice.GoogleLoginService }
05-02 15:09:04.549: INFO/Database(262): SQLiteDatabase close path: /data/data/com.google.android.gsf/databases/gls.db
05-02 15:09:04.589: INFO/ActivityManager(149): Displayed activity com.android.vending/.AssetBrowserActivity: 772 ms (total 4359 ms)
05-02 15:09:04.699: DEBUG/vending(10462): [14] RadioHttpClient.isRadioActiveElseWait(): calls going through connection type MMS
05-02 15:09:04.699: DEBUG/DataConnectionTracker(231): enableApnType(mms), isApnTypeActive = false and state = CONNECTED
05-02 15:09:04.699: DEBUG/DataConnectionTracker(231): setEnabled(1, true) with old state = false and enabledCount = 1
05-02 15:09:04.699: DEBUG/DataConnectionTracker(231): EVENT_APN_ENABLE_REQUEST 1, 1
05-02 15:09:04.699: DEBUG/DataConnectionTracker(231): dataEnabled = false, enabledCount = 1, isApnTypeActive = false
05-02 15:09:04.699: DEBUG/ConnectivityService(149): startUsingNetworkFeature for net 0: enableMMS
05-02 15:09:04.699: DEBUG/ConnectivityService(149): reconnecting to special network
05-02 15:09:04.709: INFO/vending(10462): [14] RadioHttpClient.isRadioActiveElseWait(): APN request started: Thread[GetProvisioningThread,5,main]
05-02 15:09:04.899: DEBUG/vending(10462): [1] RadioNetworkWaiter.onReceive(): Network info: NetworkInfo: type: mobile[HSPA], state: CONNECTED/CONNECTED, reason: apnSwitched, extra: wap.cingular, roaming: false, failover: false, isAvailable: true
05-02 15:09:05.639: WARN/vending(10462): [1] GetPromotedBitmapsAction.displayResults(): Failed fetching asset for assetID = -5971896071788226732
05-02 15:09:05.899: DEBUG/PrintK(88): <6>rmnet_stop()
05-02 15:09:05.919: DEBUG/MobileDataStateTracker(149): hipri Received state= DISCONNECTED, old= CONNECTED, reason= apnSwitched, apnTypeList= default,supl
05-02 15:09:05.919: DEBUG/NetworkStateTracker(149): setDetailed state, old =CONNECTED and new state=DISCONNECTED
05-02 15:09:05.929: DEBUG/NetworkStateTracker(149): removePrivateDnsRoutes for mobile_hipri (rmnet0)
05-02 15:09:05.929: DEBUG/NetworkStateTracker(149): addPrivateDnsRoutes for Mobile data state: CONNECTED(rmnet0) - mPrivateDnsRouteSet = true
05-02 15:09:05.929: DEBUG/ConnectivityService(149): ConnectivityChange for mobile_hipri: DISCONNECTED/DISCONNECTED
05-02 15:09:05.929: DEBUG/ConnectivityService(149): adding dns 172.18.7.170 for mobile
05-02 15:09:05.929: DEBUG/ConnectivityService(149): adding dns 172.18.7.170 for mobile
05-02 15:09:05.949: INFO/BootReceiver(9565): Got intent with action android.net.conn.CONNECTIVITY_CHANGE
05-02 15:09:05.959: INFO/packagechecker(10314): action:android.net.conn.CONNECTIVITY_CHANGE type:null
05-02 15:09:05.989: DEBUG/ConnectivityService(149): getMobileDataEnabled returning true
05-02 15:09:05.989: DEBUG/NetworkLocationProvider(149): onDataConnectionStateChanged 3
05-02 15:09:06.019: WARN/Smack/Packet(262): notify conn break (IOEx), close connection
05-02 15:09:06.029: DEBUG/PhoneApp(231): mReceiver: ACTION_ANY_DATA_CONNECTION_STATE_CHANGED
05-02 15:09:06.029: DEBUG/PhoneApp(231): - state: DISCONNECTED
05-02 15:09:06.029: DEBUG/PhoneApp(231): - reason: apnSwitched
05-02 15:09:06.039: DEBUG/PhoneApp(231): mReceiver: ACTION_ANY_DATA_CONNECTION_STATE_CHANGED
05-02 15:09:06.039: DEBUG/PhoneApp(231): - state: CONNECTING
05-02 15:09:06.039: DEBUG/PhoneApp(231): - reason: apnSwitched
05-02 15:09:06.049: DEBUG/Smack(262): [XMPPConn] close connection, notifyClosed=false
05-02 15:09:06.079: INFO/GTalkService(262): [ServiceAutoStarter] --- connectivity changed
05-02 15:09:06.079: INFO/GTalkService(262): [ServiceAutoStarter] --- start GTalk service ---
05-02 15:09:06.099: DEBUG/MobileDataStateTracker(149): supl Received state= DISCONNECTED, old= CONNECTED, reason= apnSwitched, apnTypeList= default,supl
05-02 15:09:06.099: DEBUG/NetworkStateTracker(149): setDetailed state, old =CONNECTED and new state=DISCONNECTED
05-02 15:09:06.109: DEBUG/NetworkStateTracker(149): removePrivateDnsRoutes for mobile_supl (rmnet0)
05-02 15:09:06.109: DEBUG/ConnectivityService(149): ConnectivityChange for mobile_supl: DISCONNECTED/DISCONNECTED
05-02 15:09:06.109: DEBUG/ConnectivityService(149): adding dns 172.18.7.170 for mobile
05-02 15:09:06.109: DEBUG/ConnectivityService(149): adding dns 172.18.7.170 for mobile
05-02 15:09:06.149: DEBUG/vending(10462): [1] RadioNetworkWaiter.onReceive(): Network info: NetworkInfo: type: mobile_hipri[HSPA], state: DISCONNECTED/DISCONNECTED, reason: apnSwitched, extra: wap.cingular, roaming: false, failover: false, isAvailable: false
05-02 15:09:06.149: DEBUG/vending(10462): [1] RadioNetworkWaiter.onReceive(): Network info: NetworkInfo: type: mobile_supl[HSPA], state: DISCONNECTED/DISCONNECTED, reason: apnSwitched, extra: wap.cingular, roaming: false, failover: false, isAvailable: false
05-02 15:09:06.169: DEBUG/MobileDataStateTracker(149): default Received state= DISCONNECTED, old= CONNECTED, reason= apnSwitched, apnTypeList= default,supl
05-02 15:09:06.169: DEBUG/NetworkStateTracker(149): setDetailed state, old =CONNECTED and new state=DISCONNECTED
05-02 15:09:06.179: DEBUG/ConnectivityService(149): ConnectivityChange for mobile: DISCONNECTED/DISCONNECTED
05-02 15:09:06.179: DEBUG/ConnectivityService(149): getMobileDataEnabled returning true
05-02 15:09:06.229: DEBUG/Tethering(149): Tethering got CONNECTIVITY_ACTION
05-02 15:09:06.229: DEBUG/Tethering(149): MasterInitialState.processMessage what=3
05-02 15:09:06.229: ERROR/HierarchicalStateMachine(149): TetherMaster - unhandledMessage: msg.what=3
05-02 15:09:06.239: DEBUG/GpsLocationProvider(149): updateNetworkState available info: NetworkInfo: type: mobile_hipri[HSPA], state: DISCONNECTED/DISCONNECTED, reason: apnSwitched, extra: wap.cingular, roaming: false, failover: false, isAvailable: false
05-02 15:09:06.249: DEBUG/MobileDataStateTracker(149): mms Received state= CONNECTING, old= DISCONNECTED, reason= apnSwitched, apnTypeList= mms
05-02 15:09:06.249: DEBUG/NetworkStateTracker(149): setDetailed state, old =DISCONNECTED and new state=CONNECTING
05-02 15:09:06.249: DEBUG/NetworkLocationProvider(149): onDataConnectionStateChanged 3
05-02 15:09:06.249: DEBUG/ConnectivityService(149): ConnectivityChange for mobile_mms: CONNECTING/CONNECTING
05-02 15:09:06.269: INFO/MediaUploader(9580): No need to wake up
05-02 15:09:06.269: INFO/ActivityManager(149): Start proc com.lookout:ConnectivityReceiver for broadcast com.lookout/.ConnectivityReceiver: pid=10482 uid=10143 gids={3003, 1007, 1015}
05-02 15:09:06.279: DEBUG/Tethering(149): Tethering got CONNECTIVITY_ACTION
05-02 15:09:06.279: DEBUG/Tethering(149): MasterInitialState.processMessage what=3
05-02 15:09:06.279: ERROR/HierarchicalStateMachine(149): TetherMaster - unhandledMessage: msg.what=3
05-02 15:09:06.299: DEBUG/Tethering(149): Tethering got CONNECTIVITY_ACTION
05-02 15:09:06.309: DEBUG/NetworkLocationProvider(149): updateNetworkState(): Updating network state to 1
05-02 15:09:06.309: DEBUG/GpsLocationProvider(149): updateNetworkState unavailable info: NetworkInfo: type: mobile[HSPA], state: DISCONNECTED/DISCONNECTED, reason: apnSwitched, extra: wap.cingular, roaming: false, failover: false, isAvailable: true
05-02 15:09:06.309: DEBUG/Tethering(149): MasterInitialState.processMessage what=3
05-02 15:09:06.309: ERROR/HierarchicalStateMachine(149): TetherMaster - unhandledMessage: msg.what=3
05-02 15:09:06.369: DEBUG/vending(10462): [1] RadioNetworkWaiter.onReceive(): Network info: NetworkInfo: type: mobile[HSPA], state: DISCONNECTED/DISCONNECTED, reason: apnSwitched, extra: wap.cingular, roaming: false, failover: false, isAvailable: false
05-02 15:09:06.669: DEBUG/Beautiful Widgets(9460): CONNECTIVITY_CHANGE
05-02 15:09:06.699: INFO/BootReceiver(9565): Got intent with action android.net.conn.CONNECTIVITY_CHANGE
05-02 15:09:06.709: INFO/packagechecker(10314): action:android.net.conn.CONNECTIVITY_CHANGE type:null
05-02 15:09:06.779: INFO/GTalkService(262): [ServiceAutoStarter] --- connectivity changed
05-02 15:09:06.779: INFO/GTalkService(262): [ServiceAutoStarter] --- start GTalk service ---
05-02 15:09:06.789: INFO/InternetConnectivityRvr(149): Network Connectivity change to false
05-02 15:09:06.859: INFO/MediaUploader(9580): No need to wake up
05-02 15:09:06.899: DEBUG/Beautiful Widgets(9460): CONNECTIVITY_CHANGE
05-02 15:09:06.939: WARN/PrintK(149): Binder Thread #(6019) sends SIGKILL to ringmode.emlist(10084)
05-02 15:09:06.939: INFO/ActivityManager(149): No longer want com.oem.engineeringmode.emlist (pid 10084): hidden #16
05-02 15:09:06.939: WARN/ActivityManager(149): Scheduling restart of crashed service com.oem.engineeringmode.emlist/.EMListInsService in 5000ms
05-02 15:09:06.939: WARN/ActivityManager(149): [ 05-02 15:09:08.259 88:0x86 F/PrintK ]
05-02 15:09:06.939: WARN/ActivityManager(149): <2>[I2C]IRQ: 90 W2 NAK (63C8)
05-02 15:09:08.259: WARN/PrintK(62): <4>Unable to drop ACPU vdd (-5)
05-02 15:09:09.563: WARN/PrintK(10482): ctivityReceiver(10482) sends SIGKILL to ctivityReceiver(10482)
05-02 15:09:09.579: INFO/ActivityManager(149): Process com.lookout:ConnectivityReceiver (pid 10482) has died.
05-02 15:09:09.989: DEBUG/PrintK(88): <6>rmnet_open()
05-02 15:09:10.119: DEBUG/PhoneApp(231): mReceiver: ACTION_ANY_DATA_CONNECTION_STATE_CHANGED
05-02 15:09:10.119: DEBUG/PhoneApp(231): - state: CONNECTED
05-02 15:09:10.129: DEBUG/PhoneApp(231): - reason: apnSwitched
05-02 15:09:10.159: DEBUG/NetworkLocationProvider(149): onDataConnectionStateChanged 3
05-02 15:09:10.169: DEBUG/MobileDataStateTracker(149): mms Received state= CONNECTED, old= CONNECTING, reason= apnSwitched, apnTypeList= mms
05-02 15:09:10.179: DEBUG/NetworkStateTracker(149): setDetailed state, old =CONNECTING and new state=CONNECTED
05-02 15:09:10.179: DEBUG/ConnectivityService(149): ConnectivityChange for mobile_mms: CONNECTED/CONNECTED
05-02 15:09:10.189: ERROR/NetworkStateTracker(149): net.tcp.buffersize.hspa not found in system properties. Using defaults
05-02 15:09:10.299: DEBUG/NetworkStateTracker(149): addPrivateDnsRoutes for Mobile data state: CONNECTED(rmnet0) - mPrivateDnsRouteSet = false
05-02 15:09:10.299: DEBUG/NetworkStateTracker(149): adding 172.18.7.170 (-1442377044)
05-02 15:09:10.309: DEBUG/NetworkStateTracker(149): adding 172.18.7.170 (-1442377044)
05-02 15:09:10.329: DEBUG/Tethering(149): Tethering got CONNECTIVITY_ACTION
05-02 15:09:10.339: DEBUG/Tethering(149): MasterInitialState.processMessage what=3
05-02 15:09:10.339: ERROR/HierarchicalStateMachine(149): TetherMaster - unhandledMessage: msg.what=3
05-02 15:09:10.339: DEBUG/NetworkLocationProvider(149): updateNetworkState(): Updating network state to 2
05-02 15:09:10.339: DEBUG/GpsLocationProvider(149): updateNetworkState available info: NetworkInfo: type: mobile_mms[HSPA], state: CONNECTED/CONNECTED, reason: apnSwitched, extra: wap.cingular, roaming: false, failover: false, isAvailable: true
05-02 15:09:10.349: DEBUG/vending(10462): [1] RadioNetworkWaiter.onReceive(): Network info: NetworkInfo: type: mobile_mms[HSPA], state: CONNECTED/CONNECTED, reason: apnSwitched, extra: wap.cingular, roaming: false, failover: false, isAvailable: true
05-02 15:09:10.359: INFO/BootReceiver(9565): Got intent with action android.net.conn.CONNECTIVITY_CHANGE
05-02 15:09:10.369: INFO/packagechecker(10314): action:android.net.conn.CONNECTIVITY_CHANGE type:null
05-02 15:09:10.369: INFO/packagechecker(10314): [ 05-02 15:09:10.489 8811:0x226b F/PrintK ]
05-02 15:09:10.369: INFO/packagechecker(10314): <2>[I2C]IRQ: 90 W2 NAK (43C8)
05-02 15:09:10.489: ERROR/PrintK(62): <3>Unable to increase ACPU vdd (-5)
05-02 15:09:10.579: DEBUG/MobileDataStateTracker(149): Requested host route to 7c371940 for mms(rmnet0)
05-02 15:09:10.899: INFO/GTalkService(262): [ServiceAutoStarter] --- connectivity changed
05-02 15:09:10.899: INFO/GTalkService(262): [ServiceAutoStarter] --- start GTalk service ---
05-02 15:09:10.939: INFO/InternetConnectivityRvr(149): Network Connectivity change to true

To get the logs for those that don't know how (I used ddms for the Gui, you can use straight adb if you know the commands). Download the Android SDK. open your command prompt or terminal window to the tools folder in the extracted adk archive. Run the DDMS app. it should fire up and start showing the logs of your connected streak (in USB debugging mode). I cleared the log just before running the market (after marking sure it was not running in the background) and once it went through its disconnect/reconnect bit I highlighted everything and saved the log to a txt file.

Anyone having this issue on a provider other than ATT?