Problems with ad's being posted on craigslist personals with my contact info:

The straight dope is, I am posting ad’s on craigslist casual encounters section W4M and Im having problems with girls modifying and posting my ad all over the country. Is there a way that I can anonymously find out where the source of these ad’s are being generated from thru craigslist’s server? It is a non-stop flow of completely vulgar responses for hours. Thank You,

Reply to them?

Bolding mine.
How do you know it’s girls doing the modifying and posting? This kind of implies you know who this is. If so, why do you need to find out?

If you are experiencing harassing responses to adds you did not post, contact Craigslist. They should have a way to report harassment and be able to do something about it.

No I do not know who it is, I suppose I just assumed it was girls, because of the whole “being a threat” aspect of how women can sometimes react to other women in a social situation

Your absolutely right about contacting craigslist directly, and I did about 24 hours ago but have yet to receive a response.