I had to add more mappacks now and runned of course into the same problem again, so I needed a solution.

Make the infostring smaller by:
1) rename all iw_*.iwd-Files to 00.iwd 01.iwd 02.iwd etc.

Load only needed .iwd's by:
2) *COPY* the files in soundaliases-folder from every mappack to fs_game/soundaliases

Without (2), impure client/ iwd sum mismatch