Installing PTB 3

Hello

I am trying to install the latest version of PTB in my Windows PC with Matlab 2011a. However, I keep getting 

"svn: E720005: Can't move 'C:\toolbox\Psychtoolbox\.svn\tmp\svn-97F204D7' to 'C:\toolbox\Psychtoolbox\PsychContributed\WinTab\TabletDemo_README.doc': Access is denied."

 

Could you please help!

Thanks