The argument to /installer should point to the full path of the *ms wmp11 setup package* (eg: wmp11-windowsxp-enu.exe), not the path to wmp11slipstreamer itself./installer:"C:\WMP11\WMP11Slipstreamer.exe"
I try to extract the installer and then look for control.xml to verify the source. However it is crashing because my brute force CAB search algo succeeds on wmp11slipstreamer itself (because it does contain an embedded cabinet file), and then fails trying to open control.xml for verification...
I suppose I will put a friendlier error message in the next version.