word files from mapped dr. cause errors

I am having a strange problem when trying to open a word document from a MAPPED network drive. Users are having a problem when in MS Word 2000 or Office XP and accessing a file from a mapped drive (named P:). This is causing word to shutdown. It is more than one person having this problem on different manufacturers pcs. The OS is 98SE. The word files are stored on NT 4.0 server with sp4. If the users navagate to the file through network neighborhood everything works ok. Any ideas