Explorer collapses

Hi everyone
2 pcs on home network, XP on mine, 98SE on the other.
When I go My Network Places - SharedDocs on Office1 (my pc) - Shared
Pictures, windows explorer disappears sometimes with the error report
"Windows Explorer has encountered a problem etc". The systray also
disappears for a few moments, then reappears without the icons which come
back several moments later. This also sometimes happens for the SharedDocs
for the other pc.
This doesn't really cause a problem because I can always go via My Network
Places - View workgroup computers and this always works OK.
Can anybody suggest what might be going wrong?
figgy