Well, seems like ICQ banned many clients with old protocol version including Pidgin 2.4.1 in my OpenSUSE 11. Here's a fix that might work for you (until there's new Pidgin version in the repository with the real fix).
Use at own risk!
- Make a backup of the ICQ library:
32-bit Pidgin:cp /usr/lib/purple-2/liboscar.so.0.0.0 /usr/lib/purple-2/liboscar.so.0.0.0.bak
64-bit Pidgin:cp /usr/lib64/purple-2/liboscar.so.0.0.0 /usr/lib64/purple-2/liboscar.so.0.0.0.bak
- Install some HexEditor (e.g.: ghex)
- Exit Pidgin if it's running
- Start the HexEditor as root and open liboscar.so.0.0.0
- Search for 0A 01 66 C7 (only 1 occurrence should be found)
- Replace the 0A by 0B and save the file
- Start Pidgin and reconnect to ICQ, should be working again
- If it worked, remove the .bak file. If not, stop Pidgin, replace library with the .bak file and you're back where you started
