Switch SCC not working

I have following s/w installed on my 64 bit Windows 7
PushOk SVN SCC 1.7.2.0
TortoiseSVN 1.7.13.24257(64 bit)
Microsoft Team Foundation MSSCCI Provider (64 bit)

While using pushok switch it gives me error
"Can not acesss registry in proper manner
Assure you have write access to HKLM\Software\SourceCodeControlProvider and
at least one SCC Provider is installed
The Parameter is incorrect."

Please advise what needs to be done in this case.