Ajit, I'm more curious about how you scheduled your diagnostic procedure to run and find the blocks. I've copied and run it, but it found nothing, because I don't think anything was actually going on at the time. Did you just run it once, or did you have it repeat periodically, knowing the approximate time the offending procedure would run?
Thanks for your question. I wrote this article 2 years ago (it was republished yesterday), and back then I used to use the diagnostic script in a job which executed the script in a loop with a pause of a few seconds (i.e. with a WAITFOR DELAY statement) and had some logic to log to a table. The script only captures details of locks that exist when it executes (i.e. at that instant).
If you are looking for a more customisable and optimised version of such a diagnostic script, I'd highly recommend MVP Adam Machanic's sp_whoisactive stored procedure. The latest version of this procedure is v11.11 at the time of writing this comment, and this can be obtained from the following location --> (http://sqlblog.com/blogs/adam_machanic/archive/2012/03/22/released-who-is-active-v11-11.aspx)
Ajit Ananthram
Blog - http://ajitananthram.wordpress.com