I had the connection issue similar to others where PT3 would no longer connect to my postgres DB. I searched this forum and came up with the solution to:
1.) Save your "data" folder. You can find it in C:\Program Files\PostgreSQL\8.3.
2.) Uninstall postgresql completely and delete everything under C:\Program Files\PostgreSQL\8.3. EXCEPT the data folder.
3.) Install PostgreSQL again, but untick "Initialize Database cluster".
4.) click on "connect" again and it should work
I did that, but now PT3 is unable to connect to my DB as it says it does not exist. The connection issue with postgres seems to be resolved, but my previous PT3 DB's seem to be missing. How can I get all my data back into my DB?