Several things could be going wrong...
As Kim says - there could be rougue/bad HTML in your code that is confusing eBid.
Use of the at '@' character anywhere in your listing can invoke eBid's email stripper which then makes a mess trying to strip out a non-existent email address.
If you paste in HTML code you should never view it in the WYSIWYG editor as it can alter it to suit its own rules on what is allowed in the code.
If you use external style sheets then if you paste in the entire HTML including the header section with the links to the style sheet then the header section will also throw the WYSIWYG editor as, as far as it is concerned, it should not exist. Again do not let the WYSIWYG editor get a look at it. Set the Plain HTML Box as your default editor and use that exclusively.
You could try posting a free listing into Whatever's Left > Test Auctions and let someone take a look and see if they can spot what the problem might be.