Unattended VDA installation fails – Installation media not found

Strange error during VDASetup for MCS:

19:47:05.5687 $ERR$ : XenDesktopSetup:Unable to read XenDesktop version details from file ProductVersion.txt Could not find a part of the path ‘C:\Windows\TEMP\wis2847.tmp\ProductVersion.txt’.
19:47:05.5687 $ERR$ : XenDesktopSetup:Unable to retrieve XenDesktop version number from ProductVersion.txt. Returning assambly version instead!
19:47:05.6937 $ERR$ : XenDesktopSetup:Installation media cannot be found

Solution: In %programdata%\Citrix was an old installation folder. I removed it. After that the installation was succesful.