We've had the same problem, Michael Pelletier addressed this question in a previous post, Check out: http://www.egroups.com/message/zope/29589?&start=29498 To summarize, 'Zope doesn't like it if there is no html tags before the DTML begins.' To fix our problem, we simply make sure that a html comment as the first line in every page, through the standard_html_header. Hope this helps, Mark ----------- mark@kaivo.com www.kaivo.com

--- In zope@egroups.com, Richard Moon <richard@d...> wrote: Marcel, you're English is fine (better than my Italian).

I think you are near to the answer.

My dtml method 'dtml_main' has this kind of logic

<dtml-if something> <dtml-var a_dtml_method> <dtml-else> <dtml-var another_dtml_method> </dtml-if>

I had standard_html_header (which has an html header) in each of the 'inner' methods, but not in the 'dtml_main' method. So I took standard_html_header out of 'a_dtml_method' and 'another_dtml_method' and put it in the 'dtml_main' method. No Invalid Header problems now. I don't know why that should make a difference but it seems to.

Thanks for your help

Richard

I found that the main dtml-method had no standard-header (so no html header) but the methods which it was rendering

At 15:01 23/06/00 +0200, you wrote:

...

...

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

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Richard Moon richard@d...

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