The URL must be missing some values, or they have been wrongly defined.

Make sure you use the following syntax when adding the variables
Eg. http://edit.br.fgov.be/edit_wp5/v1.4/areas.php?*Layers&Area Data&Area Style&*Bounding Box&Map Size

Area Data (ad=) has not been defined
This is to determin which areas will be symbolized specifically on the map in the format ad=layer name:a:area code1|b:area code2 etc
You can have information form more then one layer defined by using || as a seperator
Eg ad=layer1 name:a:area code1|b:area code2||layer2 name:c:area code1|d:area code2
The layers can only be earth, tdwg1, tdwg2, tdwg3 or tdwg4. Click on the name to see a list of the area codes.


* Items are optional
Please refer to the wiki for how to setup the service:
Wiki