[CWB] Where to change distribution instance limit

[D. Yuan]

Dear All,

I ran the query "??+[able,ability,ible,ibility]" on BNC and tried to see 
the distribution breakdown but got the following error:

--------------------

The action you have requested uses up a lot of diskspace. Your limit is 
currently set to 1000000 instances. Please contact your system 
administrator if you need access to the information you requested.

--------------------

I have changed the variable "mbstring.regex_stack_limit" to a very 
larger number than 1000000, but the error persists.

Any idea of which variable I should look for?

Best regards,

D.