You've got some superflous quotes mucking up your tag and some quotes are the wrong kind:
PostBackUrl="~/AddToCart.aspx?eid='<%#Eval("eid") %>'&ename='<%#Eval("ename") %>'"
----------------------------------^-----------------^-------^-------------------^
-------------------------------------------|---|---------------------|-----|
The positions where the caret (^) is mark the quotes that are not needed.
The positions where the pipe (|) is mark the quotes that should be single (') instead of double quotes (").
My advice to you is not to use these code tags at all but do the setting of the attributes of your tag from code behind. Code tags tend to mess up your pages tags.
Second thing I noticed is that unless "eid" and "ename" are already URL encoded strings, you'll run into trouble if they contain funny characters or event just strings. IE might swallow some that but other browswers probably wont.
Best Regards,
Manfred