Okay, so I was speaking with a friend of mine, and he suggested that the problem might be with my firewall (I run McAffee firewall).
So, I disabled my firewall, and sure enough, I was able to log in no problem, and access all functions of the application without fail.
I went to phpPgAdmin and the same thing, everything worked fine.
This would seem to indicate that the problem lies with my firewall.
HOWEVER, if the problem was with my firewall, why could I execute my test files no problem when I commented out $conn->debug = 1 ????
Further to this, could I logically expect others who have firewalls to have the same problems as I've had?
Thanks much for your help.
P.