[Upgrading, Modifying and Unlocking] Zacpod:
Yep, it's because it was running on 64 bit. I ran the extract on a 32 bit terminal server at work, and now I have a nice chunk of flash files. Next up is getting the one I need to mod mounted on a linux box - but I'll leave that for tomorrow. :)

Here's the log of the extract, if anyone is interested.

C:\Documents and Settings\xxxxxxx\Desktop>DZExtract.exe -x GW620R.dz
DZExtract v0.2 by jp

Extracting subfiles...
--------------------------------------------------------------------------------

Reading sub-header @0x13c
Checking magic number...........................Ok
Checking hash...................................Ok (779D-3AF8-DE8A-57F9-04BC-2093-441A-CAB0)
Extracting 'amss.mbn' (8717 kb).................Ok
Inflating.......................................Ok
Checking subfile hash...........................Ok (09BD-F19B-5A5F-9318-8E09-3433-802C-2147)
--------------------------------------------------------------------------------

Reading sub-header @0x883846
Checking magic number...........................Ok
Checking hash...................................Ok (2956-B022-40A3-2CD7-8D3B-2E2A-0A6D-A93E)
Extracting 'partition.mbn' (0 kb)...............Ok
Inflating.......................................Ok
Checking subfile hash...........................Ok (E292-7080-307E-BB0C-2FF4-3F79-3D31-8492)
--------------------------------------------------------------------------------

Reading sub-header @0x8839e7
Checking magic number...........................Ok
Checking hash...................................Ok (CCA4-E7AB-288B-A566-654C-E7DC-CAC8-7065)
Extracting 'qcsblhd_cfgdata.mbn' (0 kb).........Ok
Inflating.......................................Ok
Checking subfile hash...........................Ok (1AC2-9240-DCFE-6BC3-A97D-1982-395D-A261)
--------------------------------------------------------------------------------

Reading sub-header @0x883e1d
Checking magic number...........................Ok
Checking hash...................................Ok (E443-9E6E-6405-E900-4AEC-25D6-73EC-9176)
Extracting 'qcsbl.mbn' (32 kb)..................Ok
Inflating.......................................Ok
Checking subfile hash...........................Ok (422B-0D5B-6FBF-9B5F-344F-ADC7-4DD5-399B)
--------------------------------------------------------------------------------

Reading sub-header @0x88bfa8
Checking magic number...........................Ok
Checking hash...................................Ok (EE96-6604-A9B4-C510-4AC6-23EA-0420-7310)
Extracting 'oemsblhd.mbn' (0 kb)................Ok
Inflating.......................................Ok
Checking subfile hash...........................Ok (97B7-3AE9-E699-66D2-11AE-239A-0442-1482)
--------------------------------------------------------------------------------

Reading sub-header @0x88c092
Checking magic number...........................Ok
Checking hash...................................Ok (1251-FB46-F52A-A135-EA4F-6587-D4CB-8BC4)
Extracting 'oemsbl.mbn' (150 kb)................Ok
Inflating.......................................Ok
Checking subfile hash...........................Ok (9266-D1A5-E903-4DA9-D4FD-FD82-DBE6-F0E6)
--------------------------------------------------------------------------------

Reading sub-header @0x8b1a3d
Checking magic number...........................Ok
Checking hash...................................Ok (A2DE-B04A-D432-5A41-D172-6516-F19C-976F)
Extracting 'amsshd.mbn' (0 kb)..................Ok
Inflating.......................................Ok
Checking subfile hash...........................Ok (8B5F-6543-042E-D21B-FABC-75C8-806E-1AB9)
--------------------------------------------------------------------------------

Reading sub-header @0x8b1b28
Checking magic number...........................Ok
Checking hash...................................Ok (C803-0584-0556-CBB6-D84E-9E92-37E0-6DF6)
Extracting 'appsboothd.mbn' (0 kb)..............Ok
Inflating.......................................Ok
Checking subfile hash...........................Ok (46D7-EDE5-E2E6-8DCA-935F-0861-AE04-83EF)
--------------------------------------------------------------------------------

Reading sub-header @0x8b1c0f
Checking magic number...........................Ok
Checking hash...................................Ok (D524-7715-2D8F-E19E-D7EF-ED94-EE1F-AA34)
Extracting 'appsboot.mbn' (215 kb)..............Ok
Inflating.......................................Ok
Checking subfile hash...........................Ok (B0A6-3E4F-F285-D9F3-2611-FF3F-9F6C-0925)
--------------------------------------------------------------------------------

Reading sub-header @0x8e7bd0
Checking magic number...........................Ok
Checking hash...................................Ok (81FF-6E9F-0DC0-FE9D-C9A5-E0FC-0C93-3EFE)
Extracting 'zImage_Ramdisk.mbn' (2030 kb).......Ok
Inflating.......................................Ok
Checking subfile hash...........................Ok (84B3-A910-5C02-E0D0-6767-50DB-C627-569E)
--------------------------------------------------------------------------------

Reading sub-header @0xae3700
Checking magic number...........................Ok
Checking hash...................................Ok (0C8D-72E4-E649-5E84-9A4B-A34F-C555-36D6)
Extracting 'System.mbn_0' (95089 kb)............Ok
Inflating.......................................Ok
Checking subfile hash...........................Ok (54EB-94B0-7145-2142-6820-7D85-C7B0-040C)
--------------------------------------------------------------------------------

Reading sub-header @0x67bfe3f
Checking magic number...........................Ok
Checking hash...................................Ok (2DBB-3DDF-361D-6F98-F551-DDD7-F022-8A79)
Extracting 'System.mbn_1' (12158 kb)............Ok
Inflating.......................................Ok
Checking subfile hash...........................Ok (1AAE-AE6E-CCCB-107D-AC4D-1EBA-DB64-8247)
--------------------------------------------------------------------------------

Reading sub-header @0x739f892
Checking magic number...........................This is an offset table, skipping end of file

C:\Documents and Settings\xxxxxxx\Desktop>