Apparently the iToy company was again hard at work to reward their users with a even more broken experience in exchange for lots of money 
- Must have taken them a few extra engineering hours to break a previously working XCode svn setup, but they really go the extra mile for their customersâŚ
If svn works in a terminal window, does âwhich svnâ report the same path for the working svn executable as the one that DownloadPsychtoolbox reports as being used? That would be most peculiar. As @mcwilson844 pointed out, our troubleshooting tips tell you how to specify the path to the proper executable, should there be multiple ones installed. Also the same section describes how to do a manual download and setup as zip file. More disk space used, and you lose the advantages of version control, but a quick workaround.