TY: Where is this Urine smell coming from?

Back in April I made a post here:
http://www.diybanter.com/printthread.php?t 4552
I posted in this question in a few forums. Those that I remembered (the urls)I revisited and they didn't have any possible solutions. I did a search in google for my online username to see if there was any posts that I missed getting answers to. I guess I forgot this one. I'm overwhelmed with the responses.
THANK YOU to everyone who took the time to give my possible solutions in this matter it's greatly appreciated.
I haven't smelt it in months, at least summer. I will be printing off all the recommendations and making a list. But definitely, I will check for critters in the crawl space, based on many recommendations I will vent the dryer asap, and the next time I have someone on the roof (which is hopefully soon), I will get them to check that the chimney is closed off to avoid racoons.
I was getting disheartened with forums as no one was responding to many of my posts at other sites. This site has proven that the net is still a good source of information and help.
Thanks again and Merry Christmas.

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