The installation and/or snippet must have been generated wrong then...
It is working for me...
Here is an example of a member who has active auctions:
http://www.mumsonline.net/forums/mem...ns&userid=1767
And one that doesn't have any active auctions, thus its displaying most watched items from the 'baby' catagory from ebay.co.uk:
http://www.mumsonline.net/forums/mem...ons&userid=578
Here is my snippet code if it helps you debug your issues... (feel free to use it yourself, it has my affiliate code in it!

)
Code:
<script language="JavaScript" src="http://ilapi.ebay.com/ws/eBayISAPI.dll?EKServer&ai=teaodUskda&bdrcolor=666666&cid=0&eksize=1&encode=ISO-8859-1&endcolor=FF0000&endtime=y&fbgcolor=EFEFEF&fntcolor=000000&fs=0&hdrcolor=00FFFF&hdrimage=7&hdrsrch=y&img=y&lnkcolor=0000FF&logo=9&num=25&numbid=y&paypal=n&popup=y&prvd=1&r0=4&shipcost=n&siteid=3&&si=$userinfo[field14]&sort=MetaEndSort&sortby=endtime&sortdir=asc&srchdesc=n&tbgcolor=CCCC99&title=MumsOnline+-+Where+Parents+Talk%21&tlecolor=CC3333&tlefs=0&tlfcolor=FFFFFF&track=1781835&watchcat=2984&width=570"></script>
EDIT:
there is spaces rendering in the above snippet code that are not in the orginal code... Quote this message to get the snippet code as it appears in my ebay_member template