Getting InnerHTML And IE Unknown Runtime Error / Solve This?

This is not, I think, a DOM question (but it might be a DUMB question!): I've some code that sends a new string to innerHTML property (in IE) or does a element.document.write (in Netscape).

If the string I'm sending is this:

<b> some string </b>

then the code works fine in both Netscape and IE. If I change the <b> to something else, like <i>, then that works as well.

BUT: if I change it to <a> (whether or not I give the anchor any parameters) then IE complains about "Unknown runtime error". Even the anchor code works fine in Netscape.

I've not tried to systematically find out every possible HTML element that does or doesn't work. I could post all the code here, but it seems to me that sincer my code works fine with most content, there must be something "special" about sending an anchor tag through innerHTML for IE...