Weird, maybe a problem with Gold? Although I sincerely doubt it; it looks like it has something to do with the conditionals but that should be fine.
How it is right now is that you can change between the two, but to fix this for you, simply do the following then:
open the posticons template, find:
HTML Code:
<td width="12%" nowrap="nowrap"><label for="rb_iconid_0"><input type="radio" name="iconid" value="0" id="rb_iconid_0" tabindex="1" onclick="swap_posticon(null)" $iconchecked />$vbphrase[no_icon] </label></td>$posticonbits
And then just delete that