I found the answer: staroffice tries to lengthen the file using truncate(). it is usual, that in unix world it is possible. but the Single Unix Specification v.2 says, that when making truncate() with offset what is farer from file end the behaviour is undefined. In Linux 2.4, fixing vfat, they had rewritten truncate and author of vfat has realized, that it's difficult to guarantee that lengthening by truncate works and he took it out. That means, de jure it is StarOffice's fault (using such a strange feature), de facto it is kernel's fault (so thinks the fellow who has explained me all this above). Ain
After upgrading to 2.4.2 kernel (SuSE 7.0 update, rpm) StarOffice 5.2 cannot any more save files to a vfat (it doesnt matter fat16 or fat32) partition, giving general i/o error. With all other applications there's no problem. Also can I delete files or create directories with StarOffice explorer, only saving doesn't work. I have twice (with 2.4.0 kernel was the same trouble) written to staroffice newsgroup, but no reply. OpenOffice can save, but it is not yet good enough to use in production. With kernel downgrading there's also a problem, because (as someone mentioned before) SuSE won't boot with 2.2.18 kernel upgrade rpm.
Ain