PHPR Fatal Error

I just found a wired situation.

In the Events tab I try to write down the $xt-> on the last line of the event, and look what happens...
If I write $xt on the Add page of a form Before record added the next three - symbols will not be shown

The same thing happens to other events except if I write $xt in the View Page event Before Display, after I write the - symbol PHPR closes unexpectedly.
I've tried that many times and the same thing happens always. Even tried that with a news project.
Do you have any idea why that happens?
Regards,
Athanasios Alekizoglou

QUALISYS SOFTWARE