Temporary Table Problem

Dear all,
I have a strange problem.Document says that one can create a temporary table in a session. I had created a temporary table in languge plpgsql.(Actually in a procedure). After completing my task I droped a table within a seesion(In same Function). Now problem arises. When I again calles that stored procedure (Function) then it says relation does not exist . What may be the cause of that problem. It is urgent. I need ed thi function as internal function so it called again and again.

I had attached Code as well as error.

I am Using RedHat 7.1, Postgresql 7.1.2

Thanks
Dinesh Parikh
NSTL, New Delhi

Function code.
Drop Function TestTempTable()
Create Function TestTempTable()
Returns Int4 As '
Declare
DBFirst Int4;
DBRec Record;
Begin
Create Temporary Table Dual(FirstCol Int4);
Insert Into Dual Values(12);
Insert Into Dual Values(13);
Insert Into Dual Values(14);
For DBRec In
Select FirstCol From Dual
Loop
Raise Notice ''Column Value = %'',DBRec.FirstCol;
End Loop;
Drop Table Dual;
Return 0;
End;
'language 'plpgsql';

Error Appeared.

When First time run

Jurassik=# select TestTempTable();
NOTICE: Column Value = 12
NOTICE: Column Value = 13
NOTICE: Column Value = 14
testtemptable
---------------
0
(1 row)

When Second time run

Jurassik=# select TestTempTable();
ERROR: Relation 161414 does not exist