LoadRunner is unresponsive after I stop recording

Using LoadRunner 12.50 on Windows 8 I try to record uder actions on firefox and the address www.google.ch, but I get a certificate error. 

www.google.ch uses an invalid security certificate. The certificate is not trusted because the issuer certificate is unknown. The server might not be sending the appropriate intermediate certificates. An additional root certificate may need to be imported. (Error code: sec_error_unknown_issuer)

I then stop recording and after that LoadRunner is completly unresponsive. I have to use the task manager to shut it down forefully!

Does this version of LoadRunner has problems/issues/bugs? I am not ablte to use it in any case!!