I couldn't figure out how to get this into Gemini, so I'm sticking it here hoping it gets some traction.  When you first install the module, the shipping is set to 0.  The validator expects #.## format, and fires when an unrelated linkbutton is clicked (such as updating tax rates or switching to Categories).  Changing the vale to 0.00 solves the problem temporarily, but the value reappears as 0 when you leave the admin screen and return.  Also, two error messages pop up (this was recorded in Gemini but marked as completed).

Three suggested fixes:

1) Default shipping to 0.00

2) Make sure validator only fires when the Update Shipping Cost is clicked.

3) Have only one error message open.