[Sajeth]

Your long story short: you have very little experience in optimizing code for all browsers and web development in general.
First, YES, Internet Explorer does a lot of strange things, one of those strange things is giving useless error messages when the code in fact is valid.
Second, NO, there is not the slightest need for such messages in a live environment.
Third, if you get a "real error", propably the last thing you need to notice it is getting another MIE error message. And in debug mode, those errors are shown anyways.