Sergey,

I doubled checked variable declarations and confirmed that @s1_count is declared as integer.
When I run the above statement in Query Analyzer the result is 28 ...and no error message:

declare @fib_lot char(6)
set @fib_lot = '030363'
SELECT count(fib_s1) from dsiweb.dbo.s2p2_results
where fib_s1>0 and inst_type='S'
and fib_lot = @fib_lot

Thank you,
Daniel