[Nexus 5 Themes and Apps] mistersixt:
Thanks for the hint, the error message is at least different now:

mistersixt@mars:/tmp# ./apktool if framework-res.apk
I: Framework installed to: /root/apktool/framework/1.apk
mistersixt@mars:/tmp# ./apktool b SystemUI
I: Using Apktool 2.0.2
W: Could not find sources
I: Checking whether resources has changed...
I: Building resources...
/tmp/SystemUI/res/layout/keyguard_emergency_carrier_area.xml:5: error: Error: No resource found that matches the given name (at 'text' with value '@android:string/permlab_reboot').

/tmp/SystemUI/res/anim/ic_qs_signal_blink_1.xml:4: error: Error: Integer types not allowed (at 'valueType' with value '3').

/tmp/SystemUI/res/anim/ic_qs_signal_blink_2.xml:4: error: Error: Integer types not allowed (at 'valueType' with value '3').

/tmp/SystemUI/res/anim/ic_qs_signal_blink_3.xml:4: error: Error: Integer types not allowed (at 'valueType' with value '3').

/tmp/SystemUI/res/anim/ic_signal_blink_1.xml:4: error: Error: Integer types not allowed (at 'valueType' with value '3').

/tmp/SystemUI/res/anim/ic_signal_blink_2.xml:4: error: Error: Integer types not allowed (at 'valueType' with value '3').

/tmp/SystemUI/res/anim/ic_signal_blink_3.xml:4: error: Error: Integer types not allowed (at 'valueType' with value '3').

Exception in thread "main" brut.androlib.AndrolibException: brut.androlib.AndrolibException: brut.common.BrutException: could not exec command: [/tmp/brut_util_Jar_7373949509298300830.tmp, p, --forced-package-id, 127, --min-sdk-version, 23, --target-sdk-version, 23, --version-code, 23, --version-name, 6.0-eng.clyde.20151007.150204, -F, /tmp/APKTOOL1436657618575203167.tmp, -0, resources.arsc, -0, arsc, -I, /root/apktool/framework/1.apk, -S, /tmp/SystemUI/res, -M, /tmp/SystemUI/AndroidManifest.xml]
at brut.androlib.Androlib.buildResourcesFull(Androlib.java:465)
at brut.androlib.Androlib.buildResources(Androlib.java:403)
at brut.androlib.Androlib.build(Androlib.java:291)
at brut.androlib.Androlib.build(Androlib.java:261)
at brut.apktool.Main.cmdBuild(Main.java:225)
at brut.apktool.Main.main(Main.java:84)
Caused by: brut.androlib.AndrolibException: brut.common.BrutException: could not exec command: [/tmp/brut_util_Jar_7373949509298300830.tmp, p, --forced-package-id, 127, --min-sdk-version, 23, --target-sdk-version, 23, --version-code, 23, --version-name, 6.0-eng.clyde.20151007.150204, -F, /tmp/APKTOOL1436657618575203167.tmp, -0, resources.arsc, -0, arsc, -I, /root/apktool/framework/1.apk, -S, /tmp/SystemUI/res, -M, /tmp/SystemUI/AndroidManifest.xml]
at brut.androlib.res.AndrolibResources.aaptPackage(AndrolibResources.java:425)
at brut.androlib.Androlib.buildResourcesFull(Androlib.java:451)
... 5 more
Caused by: brut.common.BrutException: could not exec command: [/tmp/brut_util_Jar_7373949509298300830.tmp, p, --forced-package-id, 127, --min-sdk-version, 23, --target-sdk-version, 23, --version-code, 23, --version-name, 6.0-eng.clyde.20151007.150204, -F, /tmp/APKTOOL1436657618575203167.tmp, -0, resources.arsc, -0, arsc, -I, /root/apktool/framework/1.apk, -S, /tmp/SystemUI/res, -M, /tmp/SystemUI/AndroidManifest.xml]
at brut.util.OS.exec(OS.java:89)
at brut.androlib.res.AndrolibResources.aaptPackage(AndrolibResources.java:419)
... 6 more
root@mars:/tmp#