No extrusion when X beyond a limit (no replies)

On my Delta printer the extruder stops feeding if X >90mm or if X <-90mm. On a print with a max X dimension of 193mm this results in very rough parts on the printing. There are many pictures on [reprap.org]
An additional symptom is that the skirt - 3 loops at 6mm from the print, does not print even though visible on the Repetier host preview.
I have looked at the host settings, EEPROM settings, host settings and even the Repetier firmware configuration files but nothing is obviously wrong.

Thanks for any help or pointers you can give.

Mike