Several error messages are combined in this FAQ. If you find another one, and a solution for it, please let us know.
Note: as of TSVN 1.2.0, Windows 95/98/ME and Windows NT4.0 are no longer supported.
To solve this problem, clear the temp folder, move the installer msi file to your local harddrive where the user SYSTEM has full access rights.
The following knowledge base articles may help: