SERIALIZABLE TRANSACTION Getting Blocked?

Hi guys,

I have a stored procedure which generates the next sequence number...
it uses SERIALIZABLE Option. procs look something like below..

begin
SET TRANSACTION ISOLATION LEVEL SERIALIZABLE
BEGIN TRANSACTION

Sequence generating statement...

COMMIT TRANSACTION
set @NextSequenceValue = @NextSequenceValue
Return @NextSequenceValue
end

For some reason when i call the proc with below parameters to get next sequence number.. its hungs up..


declare @NextSequenceValue int
set @NextSequenceValue = 0
exec spGetNextSequence 19, 'LotSequence', @NextSequenceValue output, Null
select @NextSequenceValue as NextSequenceValue


When i queried sp_who2 it shows that my processid is blocked by some other processid.. and when i do DBCC INPUTBUFFER (blockingprocessid), the query of blocking processid and my nextsequence generation stored proc is not realted at all..

Can you help shed some light on why my nextsequence generating proc is getting hunged...?

help is appericated..