Hi Hugo,
Server Port is not the problem. Have a look on scenarios below:
I have looked into the code. We are using value from HTTP HOST environment variable.
The code is quite messy
..let me not get into explaining it to you
...
Apache:
Portnumber : other than default(80)
HTTP HOST: <IP Address:Port Number>
Portnumber : default (80)
HTTP HOST: <IP Address>
Hiawatha:
Portnumber : default / other than default(80)
HTTP HOST: <IP Address>