error when saving to mapped drive

I am running office 2000 on a w2k machine. Whenever I try to save a document to a mapped drive I get this error message
“AN error occured when reconnecting E: to \\servrname\folder Microsoft windows network. The local device name is already in use. This connection has not been restored”
This comes up twice and then the file is saved.
I’ve had similar problems with mapped drives were you get an error message and the file is saved anyway.

Does anyone have any ideas what the source of the problem could be ?