ERROR: function crosstab(unknown, unknown) does not exist

Hi there,

I am using 9.1.3. I inserted the tablefunc extension, into a SCHEMA called tablefunc, in order to separate it from my
tables.I had to create it as postgres user, but changed than the Owner of both schema and functions to my user XXX. 

Now, when I launch a query which includes "crosstab()" as a postgres user, everything works fine. However, if I launch
itas user XXX, it complaints: 

     ERROR:  function crosstab(unknown, unknown) does not exist
     LINE 1: ...ROM countries_view AS c LEFT JOIN ( SELECT * FROM crosstab( ...
              ^ 
     HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

     ********** Error **********
     ERROR: function crosstab(unknown, unknown) does not exist
     SQL state: 42883
     Hint: No function matches the given name and argument types. You might need to add explicit type casts.
     Character: 84


I looked for the other tables which are included in the query, if they belong to postgres, but they belong all to user
XXX.

So, what could that be?

Thanks for any hints!