Caron Diacritic Diplay Issue + Member ID Question

[Hikarin]

Hello, there seems to be a problem on my forum and other vB4 forums that I know, in which the caron diacritics for a, i, o, and, u display as though separated (it displays fine over e, though).

The odd part is, is that it only looks that way when viewed through Chrome and Opera. It looks fine if you're looking at the page on IE or Firefox.

What is Chrome and Opera doing for it to affect it like this? You can view these carons fine on other websites on said browers, so what is the conflict? Please help me to resolve this issue.

For those who this diacritic talk went over the tops of their heads, below are the characters I am talking about.
ǎěǐǒǔ

Also, as a separate question, I have sort of retconned my website. As such, I have deleted the old members but kept the base idea of the site active.
However, any new members I add are added by the next available user number (e.g., there were 30 members before I deleted them, the new member receives the ID number of 31).
Is there a way to reset this count?