The description suggests to me that either:
a) the problem documents were created on a different server and cannot therefore find their templates
b) the problem documents were created on the same server but the template has been deleted or renamed and the documents cannot therefore find their templates;
c) you have faulty network (hardware and/or software); or
d) there is a fault in the user's network profile.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]