Problems accessing MS publisher files over network

I recently purchased the Microsoft MN-820 wireless
package for my home PC's. I am having a strange problem
where for some reason I am unable to open MS Publisher
files over my home network. All other types of files
work fine (i.e. excel, acrobat, word, etc...), but the
publisher files give me an error message saying
"file is locked because it is currently being used
by another program. Please close the other program
and then try opening or importing the file again."
The problem is that there is no other program open on any
other computer. I also cannot access these files to copy
and paste them from one machine to another. I have tried
rebuilding both machines, which temporarily resolved tghe
issue, but it is beginning to happen again...Any ideas or
help would be much appreciated... Thanks