I tried to follow the example of a let tag in "DTML User's Guide". I tried made a DTML Method with the following code: <dtml-in "1,2,3,4"> <dtml-let num=sequence-item index=sequence-index result="num*index" <dtml-var num> * <dtml-var index> = <dtml-var result> </dtml-let> </dtml-in> When I click on Change, I have the message: invalid parameter: " Similarly, I tried the example in the HOW-TO: let Tag: <dtml-let name="bob"> relation="uncle" <dtml-var name> is your <dtml-var relation> </dtml-let> I can click on Change, the problem is when I go the URL of the method, I get message: Zope Error Zope has encountered an error while publishing this resource. Error Type: NameError Error Value: bob ...What's wrong?