Hi,
Looking at the error message you are getting seems like you need to take help from basis and ask them to check the time out error. Also you can try to broadcast report with blank data (so that it will be real quick in order to avoid that time out error).
Second I will try to broadcast it via RSRT.
Run the query ( select HTML type) and after getting the output, try to broadcast it from there.
In this way you will be able to find is there any issue with Portal or Broadcaster itself.
Thank-You.
Regards,
VB