The Rename method renames the logical file (or directory) specified in the object path. Rename returns an integer value of ...

The Rename method renames the logical file (or directory) specified in the object path. Rename returns an integer value of 0 if the file was successfully renamed, and any other number to indicate an error. A rename is not supported if the destination is on another drive or overwriting an existing logical file is required
It returns one of the following integer values:
0 - The request was successful.
2 - Access was denied.
8 - An unspecified failure occurred.
9 - The name specified was invalid.
10 - The object specified already exists.
11 - The file system is not NTFS.
12 - The platform is not Windows NT or Windows 2000.
13 - The drive is not the same.
14 - The directory is not empty.
15 - There has been a sharing violation.
16 - The start file specified was invalid.
17 - A privilege required for the operation is not held.
21 - A parameter specified is invalid.