Gmap Error "Javascript is required to view this map" when using with Finder

In my drupal 6 site, I use Finder embedded in a node, to search for another node.
When user select a result, the node is loaded in the same page.
The final structure is

- parent node
- finder embedded
- parent node description
- resulting node (the one with the gmap field that should appear)

Everything works fine, except that the map loaded in the resulting node is not displayed.
I get this error "Javascript is required to view this map".
First I thought my problem were missing js, so I've put _gmap_doheader(); in my page_preprocess to ensure all js were included and they actually are.
But I still get "Javascript is required to view this map".

What's wrong with it?