A couple of questions... What character are you trying to load? How many characters of the same generation do you have installed? Does the character eventually load or does it never proceed further than 50%?

It sounds like your load process is stopping during the morph loading procedure. My first step would be to check the Error Log (Help > Troubleshootiing > Error Log) and see if that gleans any useful information. After that I would try uninstalling the last character / morphs you installed.