Thanks to Jugney, both problems solved.

1. The user_func_array error is caused by using a version of Ubercart which does not support other product types. If the required modifications for uc_event in uc_cart do not occur on line 1851 then chances are you are using a buggy version. I used an rc version, probably April 4 or April 23 (http://drupal.org/node/129292/release).

NOTE: this thread: http://www.ubercart.org/issue/5332/add_cart_form_with_new_productnodetyp... describes the problem and how to fix it. I upgraded to Ubercart 5.x-1.0 and got this error. Making the patch solved it.

2. The doubling up of add to cart links has been fixed and new code uploaded to the project page, see link above.

I welcome any more probs. It may be a good idea to post at the project page rather than here. Go to http://www.ubercart.org/contrib/5306.

Thanks again to Jugney. These modules don't get refined without your testing them and giving feedback.