Hi there Garrog,
AVStoDVD installer package queries the following Windows registry entry to detect a previous Haali installation:
HKEY_LOCAL_MACHINE\SOFTWARE\HaaliMkx\Install_Dir
If Haali has been installed correctly, then that key will be present.
About using the release 1.11.288.0, I cannot guarantee its compliance. If you test it and get no issues, please report it back. Thanks!
Take note that last official Haali release is 1.11.96.14 (http://haali.su/mkv)
Bye