The system cannot find the path specified

Hello, everybody!
I am developing a backup software. So, when I add a file to the backup list,
it is copied into some temp directory:
(For example: file - e:\dir1\dir2\dir3\file.ext
temp directory - c: emp
result - c: emp\e\dir1\dir2\dir3\file.ext).
Then I pass the root directory (c: emp) to NERO.
But when I try to burn CD, I sometimes get the next message in the log file
“The system cannot find the path specified” and the burning process lasts
long time after that. Have someone met the problem? Please, help me.