Firebird 2.1 on Linux 64-bits. (LI-V2.1.0.17798)

The last two nights during normal backup and restore of one of our databases we got segmentations faults when restoring with gbak (gbak -r).

The scripts, started with crontab, returned the following messages:
01/07/2009:
/ibdata/auto/back_gen.sh: line 346: 8804 Segmentation fault $GBAK -r -p 4096 $BACK2 $REST $ID 2>>$LOG
02/07/2009:
/ibdata/auto/back_gen.sh: line 346: 13081 Segmentation fault $GBAK -r -p 4096 $BACK2 $REST $ID 2>>$LOG

At the corresponding times I found these two lines in /var/log/messages:
Jul 1 00:47:36 eminux kernel: gbak[8804] general protection rip:2afb0ae3638b rsp:7fffa00b6510 error:0
Jul 2 00:44:55 eminux kernel: gbak[13081]: segfault at 00002af590020000 rip 00002af58a9ac1cf rsp 00007fff203a1890 error 4

Starting gbak manually in the morning did not return any error and works fine, so its difficult to reproduce the error.

Has anyone an idea what could have caused these errors or how to get more information?

Thanks,

Stefan