If the above code doesn't work to pull your information, try using the alternate code used by SigGen (it's been changed between the two a few times.)
Replace:
Code:
<a href="http://www.YOURFORUMS.com/roster/index.php?p=char-info&member=$post[username]"><img src="http://www.YOURFORUMS.com/roster/index.php?p=util-siggen&mode=signature&member=$post[username]@REGION-SERVER" border="0" /></a>
With:
Code:
<a href="http://www.YOURFORUMS.com/roster/index.php?p=char-info&a=c:$post[username]"><img src="http://www.YOURFORUMS.com/roster/index.php?p=util-siggen-signature&a=c:$post[username]@REGION-SERVER" border="0" /></a>