Error message: "Cannot open file. Verify that the path and..

.....filename are correct and try again.=20

Happens with many files although some open fine. They are named=20
something normal with no strange characters or spaces in the name, .wmv=20
as the suffix, and I place them in the top level of my drive so the path =

should be simple. Help! I tried double clicking, I tried selecting =
"File: Open"=20
and nothing seems to work. Any ideas?

Cannot open file. Verify that the path and filename are correct and try =
again.

That is the error message in its entirety.