I installed the ACL Manager and because of the site errors it was unable to run.
Sander in support replied in less than 10 minutes and with access to the database and eventually the site, fixed it. I cannot recommend this quality of service enough and it is embarrassing that it only cost €15 for 6 months support.
If you are like me after spending hours on google trying to find answers save your self the problem and install this if only for the support.
I am using 2.5.9 and installed the plugin at the last position as detailed in the documentation.
We have just released a new version with may fixed your issue. Try it now :)
Very professional service and makes our 1.7 site a lot more attractive.