Trader - just print the @SQL first - your error will likely pop right up at ya... If you don't see it - paste it into a new query window and see what the parser has to say about it.

Meaning

...

Print (@SQL)

Exec (@SQL)

Also - You can't "build and execute" at the same time. EXEC wants a static string (meaning - something fully built before you pass it to execute), not some concatenation operation happening inside the EXEC statement.