ok with the new version, the first icd-error has vanished.
but right after the icd2-error, the script hangs sometimes (I canceled after like 4 minutes…) Apparently, it only hangs if I'm not connected to either GPRS or WLAN (but not always, when I'm not connected). If it hangs, I can go to the connection-selection menu (no need to select a connection, just go there) and the script continues.
The next thing I noticed: When I didn't have a connection before, the backend closes the connection when I stop it. But when I wanted to connect to GPRS manually after that, the GPRS-Connection was not there, just the WLANs!