It's not a simple thing to do and it can be implemented in different ways. Take a look at
- article 'Error handling in VFP' by Doug Hennig at http://stonefield.com/techpap.html
- the error handler project at http://www.ideaxchg.com/ix07/er/_sys/toccontu.htm
- In VFP8 the Structured Error Handling was introduced http://www.code-magazine.com/focus/Article.aspx?quickid=0301072.


>In my mian prg I use following codes to handle error routine
<snip>>
>It works fine, but the problem is when some error window appears with OK button, I press OK button then programm immediately quits and exe is closed.
>
>I want when error window appear, by pressing OK button the program must not be close.
>