I used Boinc4.06 on WIN98SE.
When CP start (switch from Seti to CP) follows message:
SETI@home - 2004-09-01 13:59:13 - Preempting result 04my04aa.14406.25968.40912.191_2 (quit)
climateprediction.net - 2004-09-01 13:59:13 - Starting result 045l_000030375_0 using hadsm3 version 4.03
climateprediction.net - 2004-09-01 13:59:15 - Unrecoverable error for result 045l_000030375_0 ( - exit code -2 (0xfffffffe))
climateprediction.net - 2004-09-01 13:59:15 - Deferring communication with project for 1 minutes and 0 seconds
climateprediction.net - 2004-09-01 13:59:15 - Computation for result 045l_000030375 finished
SETI@home - 2004-09-01 13:59:16 - Restarting result 04my04aa.14406.25968.40912.191_2 using setiathome version 4.03

There are issues about running BOINC on Win98.

This is from the SETI/Boinc site:-

August 30, 2004
We are investigating the Win98 hang/crashing issues in this Thread Please check it out for any updates.
NOTE: This bug puts your machine in a state that causes you to reset your machine in order to be able to use it, this in turn can cause disk corruption. We recommend that you hold off executing BOINC on Win98 and WinME until this issue is resolved.

See this thread on that site:-

http://setiweb.ssl.berkeley.edu/forum_thread.php?id=3376


K.

With the new http://setiboinc.ssl.berkeley.edu/boinc_alpha/download/boinc_4.06_windows_intelx86.exe
run Seti but not CP.