Just a simple observation based on your responses here.
By chance are you enabling ad types in the admin edit ad types section that you are not creating categories for under edit categories in admin.
For instance if the only ad type your going to use is FOR SALE then only have that one enabled and the categories you create would be assisnged to for sale. If you want to enable wanted personals etc then you would have to create categories to use that template type. Otherwise when a user goes to upload and they select wanted then no categories are going to show because you have not created categories to use that template type.
make sense now?
I would think thats your issue. I can not say for sure since you have your site set so that guests can not view anything.
You would turn OFF any ad types you have not made a category to use it. I can not offer any advise about anything given the fact you have locked your site from viewing to the public. I can only base my replies off what your saying is happening since I can not see the issue.
You can send an admin login through the contact us link in our site header to look at how you have it setup.