cannot copy files

[Guest]

when I try to move a file from pc A to pc B, I get a message that says " cannot copy *** : access is denied. The source file may be in use." I can, however, while operating pc B, copy the same file FROM pc A to pc B.... ????
What am I doing wrong?

 

[Bob I]

Please also specify the method you are using to "move" the file.