Yeah, well, your use of qcop is simply as a messenger, to tell the appropriate application it should open the file.
If you want textedit to open the file, then try something like (untested):
qcop QPE/Application/textedit 'start(QString)' 'hello.txt'
Use the qcoptest app I described at
http://www.sdjf.esmartdesign.com/ipks/qcoptest.html to test your syntax without crashing.
You also may need to google or search here for examples of successful qcop calls.
I also found running strace to be quite helpful in figuring out the causes of crashes.
Cheers,
sdjf