Section Wizard Import Error

Hello, 

I have created a built-up section in section wizard and am trying to import it into my STAAD model. When I try to add my .upt file I receive this pop up:

The file I am trying to use does not contain any "-" nor any other special characters. See .upt file name here;

Any idea why I am getting this error? or how I can work around it. 

Thanks