"Invalid Page Fault in MFC40.dll" or "Invalid Page Fault or GPF in Netscape Mail."
Caused by corrupt mailboxes.
Exit out of Netscape Mail.
Locate files named "inbox" and "inbox.snm". Rename them and restart the mail program.
To locate the files click on <Start><Find><Files or Folders>
In the Named filed type in "inbox" make sure you are looking in teh C: Drive and click on <Find Now>. Do the same with the "inbox.snm" file.
Once you have located the files click on them once and then on the top tool bar click on <File> and the select <Rename>.
Rename the files to "inbox.old" and "inbox1.old" respectively.
Restart Netscape Mail.
If the problem is with another box (ie. Outbox) follow the same procedure but with that box name.