[Zope] R: [Zope] Invalid Header (0) error

[Marcel Preda]

> Does anyone know what an Error Type: Value Error, Error Value:Invalid 
> Header (0) error represents ?
> 
> It's interesting in the way it shows itself up. I added a <dtml-var 
> a_dtml_method> to a dtml method and it generates this error. This <dtml-var 
> a_dtml_method> is nested inside a <dtml-if> and would definitely not be 
> rendered the first time the 'calling' dtml-method is rendered.
> 
> I took out the <dtml-var a_dtml_method> and I still got the same error.
> 
> I put a <dtml-var REQUEST> as the first line of the 'calling' method and 
> everything then renders correctly with no error. Even the <dtml-var 
> a_dtml_method> renders correctly when it should do so.
> 
> Any ideas, suggestions ?
> 

This is very strange.
I had have the some problem.
I have seen that if the Zope generate a lot of empty lines at the begining 
I receive this error.

the idea is to dont have too many empty lines at the begining of the output,
(I have no idea how many)

try to write something at the begining of the output doc.
I use someting like "Content-type:...."

PM
PS: My English is not so good, 
maybe you dont understood what I want to say