Have you ever come across the following error on one of your ASP scripts?

Microsoft VBScript runtime error ‘800a0005’

Invalid procedure call or argument: ‘InStr’
/My_Page.asp, line 94

Now the function throwing this error can be any of the standard ASP string manipulation functions, namely Left(), Right(), Mid() or InStr() and usually it comes as a bit of a surprise because this function is almost impossible to call incorrectly, unless you are going past the string