Well, if it says it is owned by another user, i think it would mean that someone else on the hosting server has the exact same subdomain you are trying to enter.

I'll let Alex confirm if this is true or not, since I have never seen that message before therefor I don't really know what it means.

i do not want to do that, and that domain and all associate with it is purely with t35. also you can have a sub domain with the same name on 2 different domains. just have to change the folder that it references to in cpanel. but the weird thing is is that i can add one sub sub domain, after that i get the error. and the odd thing is is that no one else can have the same exact address, cause they would have to add the main domain first and cpanel wouldn't do it if someone else already created it.