If trying and install Linux with many partitions (/, /usr,
/usr/local, /home, /tmp, ......) which obliges Linux to
create an extended partition, this partition is detected by
Windows 98 as a new logical disk (which produces a pretty
good looking offset in the drives letters). This is not like
that with Windows NT.
The solution i took was to create only 3 large partitions :
/, /usr and SWAP, but that's not fair with UNIX
This is not a bug, but rather the way that Win98 is treating linux partitions.
You said yourself that NT does not have this problem.