MB-String overload, how to change the settings?

[drumlover]

Hey,

this is probably a really dumb question but I would like to know where I can change the MB String Overload?
I already searched for a good explanation but I still haven't found one.
The problem is that I want to offer Joomla Support, but there is no real support possible if Joomla won't run properly and it needs to have the MB String Overload set to 0... Off...

I would appreciate it very much if you could answer...

Best regards,

drumlover