I have a nikon F50 with which I use a 35 - 80mm AF Nikkor zoom lens. The combination was working fine until I coupled the body to a Bowens Illumitran slide duplicator to test if it was working (the Bowens). I have used the camera many times on another Bowens Illumitran in Manual mode with no problem, but as I only wanted to test the duplicator I didn't load a film into the F50 and set off taking approx 7 - 8 exposures. Everything worked fine during the test, but now the camera has "ERR" flashing in the LCD display (with no other symbols) and the shutter release is locked. The only other indications in the LCD display are P for program mode and [E] indicating no film loaded. I've tried switching off & back on, replacing the battery and pressing the film rewind button on the camera base, but nothing seems to work. Also, it is impossible to load a new film. Does anyone know how to cure this problem or is it a visit to a professional repairer ? I would appreciate any help to overcome my dilemma....Thanks in advance....axion123

It could be dirty contacts on the lens or body. Remove the lens and try cleaning the contacts. Do not use anything abrasive. Alcohol wipes are good. An eraser (like you get on the end of a pencil) is very good for cleaning contacts but be careful not to get any dirt inside the camera or on the lens.
Best of luck
Don

Hi Don....

I've tried your suggestion and cleaned both sets of contacts with Iso Propyl Alcohol on a cotton bud....but unfortunately it hasn't rectified the problem. Many thanks ... it was worth a try !

Err means "something mildly serious is wrong" - it's a bit like Err 99 on a Canon and a GPF in Windows - something is wrong but the camera isn't sure what You can try using a new card (and actually this should be one of the first steps to trouble shoot a camera).