[Zope] dtml document bug

[Dmitry Slusarchuk]

I'm new to Zope development but I have already encountered such a problem:
<dtml-var myimage> from dtml document generates the following:
Zope Error
Zope has encountered an error while publishing this resource. 

Error Type: AttributeError
Error Value: __call__

this problem disappears when I do smth like <dtml-var myimage>
from dtml method. what should I do?

In addition 
I run Zope ver. 2.2.2 and Python 1.5.2 under Win98.

Thanks to ev'body for a HELP!