Figured it out...

[sbox-SDK_PC: ~] > sbox-config -er /scratchbox/packages/Maemo_Dev_Platform_RS_v1.1rc5_i386.tgz
Extracting /scratchbox/packages/Maemo_Dev_Platform_RS_v1.1rc5_i386.tgz to /targets/.tmp/SDK_PC
Moving /targets/SDK_PC to /targets/.old/SDK_PC
Moving /targets/.tmp/SDK_PC to /targets/SDK_PC
Restarting Scratchbox shell...
Hangup
Shell restarting...
[sbox-SDK_PC: ~] >

Was not working correct for some reason??? So the complete package was not unpacked...