Crosstab function Problem

Hi,
I am having problem using the crosstab function ( which is under the contrib/tablefunc directory). I have installed the tablefunc module and also installed the functions into my DB.
I am using postgresql 7.4 beta version.

I am issuing the following query,

select *
from crosstab(
'select path,name,value
from file f, metadata m
where f.id = m.file_id
and f.type=1
order by 1,2;',3)
AS DP(name text,runid text, plottype text,region text) ;

I am getting the following error message.
No function matches the given name and argument types. You may need to add explicit typecasts.

I also issued the given example in the tablefunc directory and it gave the same error.

Help me out with this,
Kuldeep.