So, one light and button is working. I don't know how many x10-modules you have but have you tried out these other modules with the same housecode (P) and devicecode and button as the one that is functioning?

If they don't work try this again by testing all x10-modules one by one in that wallbox that is functioning.

If they now respond, set the module to a different devicecode. If it's still responding then nothings wrong with iPronto-communication.

If not: Maybe you need a fase couppler?

Kees