Problem executing user function (on Solaris)

Hi,

I am using plpgsql to write user function and type.
I am facing problem while executing the function.

psql=# select * from GSS_FUNC_REQ_CDR_COUNT();
ERROR:  parser: parse error at or near "("

psql=# SELECT  GSS_FUNC_REQ_CDR_COUNT();
NOTICE:  plpgsql: ERROR during compile of gss_func_req_cdr_count near
line 0
ERROR:  fmgr_info: function 0: cache lookup failed

psql=# \df  GSS_FUNC_REQ_CDR_COUNT
 List of functions
 Result data type |          Name          | Argument data types
------------------+------------------------+---------------------
 gss_counter_type | gss_func_req_cdr_count |

I am using PostgreSQL 7.4.3 on Solaris 5.8

BUT,If I try the same stuff on my Linux box(Debian 2.4.4-pre3+,i686),
things are working fine.
psql=# select * from GSS_FUNC_REQ_CDR_COUNT();
 store_drt | acked_drt | store_cdr | acked_cdr
-----------+-----------+-----------+-----------
       400 |        12 |       400 |        12

Can anybody suggest, How to solve this problem?

Thanks,
Rajan Bhide