Comments by Jose Pla (Top 1 by date)

Change
SELECT @SQL = 'SELECT * FROM #OutPutTBL'
for
SET @SQL = 'SELECT * FROM #OutPutTBL'

if you still get nothing it could be temp table, you might try using a global temp table
##OutPutTBL instead of just #OutPutTBL

http://msdn.microsoft.com/en-us/library/ms187330.aspx
http://msdn.microsoft.com/en-us/library/ms189484.aspx

Also make sure you have already declared the variable @SQL
DECLARE @SQL varchar(500)