How to use custom validator in this case?

Question

I have textbox1, textbox2 , button1, button2 and linkbutton1 i have added custom validator to that textbox1 and textbox2 and keeping the same valiadtion group to textbox1, button1. Another same validation group to textbox2 and button2. Custom validator is for invalidate character i.e # & < >.

If i click on button1, button2 then it give error fine, but i click on linkbutton1 my page get crashed .

So how to prevent this crashed ???? Please tell me.