It looks like our last response to the user may have resolved the issue. I apologize for not having it posted here, but this is due to not being able to confirm that it did work for the user. Here is the response:
You are correct, this is an issue with IE only with the date picker. To resolve this issue, try replacing the onblur in this line:
<input id="Add_Invoice_group_Invoice_Date" name="Add_Invoice_group_Invoice_Date" type="text" value="" class="formTextfield_Medium" tabindex="2" onblur="hideServerError('Add_Invoice_group_Invoice_Date_ServerError');"/>
to onfocus:
<input id="Add_Invoice_group_Invoice_Date" name="Add_Invoice_group_Invoice_Date" type="text" value="" class="formTextfield_Medium" tabindex="2" onfocus="hideServerError('Add_Invoice_group_Invoice_Date_ServerError');"/>
remember that this will solve the issue, but if you reenter the wizard, then this change will be overwritten.