I have the same kind of errors.
So I tried with starting a blank new project using WordPress (english) 3.3.2
Only plugins installed :
NextGen Gallery, version: 1.9.3
NextGen Gallery geo, version : 0.60
All running locally with MAMP (on Mac, OS X Lion)
Only one post ! With [nggallery id=1] [nggg]
Before I tagged the post, I had the same error as Aviceda.
Once the post tagged, I have the same error as alternateroute.
I am not sure what we should understand by "You have to add the plugin tag, otherwise your post is not related to the plugin." ?
Do you mean to add a tag for the post like "nextgen-gallery-geo".
Whatever, it's what I did.
When trying to update the options of the plugin, I get again the error message :
Cannot modify header information - headers already sent by (output started at /.../wp-content/plugins/nextgen-gallery-geo/example.php:145) in /.../wp-includes/pluggable.php on line 866
and I get a full list of errors for the preview map.
I get the same message if I do an update for the post.
If I display the post, I get a list of error :
Notice: Undefined variable: map_output in /.../wp-content/plugins/nextgen-gallery-geo/plugin.php on line 25
Warning: exif_read_data() [function.exif-read-data]: Unable to open file in /.../wp-content/plugins/nextgen-gallery-geo/functions.php on line 24
Notice: Use of undefined constant latitude - assumed 'latitude' in /.../plugins/nextgen-gallery-geo/functions.php on line 144
Notice: Use of undefined constant longitude - assumed 'longitude' in /.../wp-content/plugins/nextgen-gallery-geo/functions.php on line 145
Notice: Use of undefined constant latitude - assumed 'latitude' in /.../wp-content/plugins/nextgen-gallery-geo/functions.php on line 67
etc... for several lines...
I like very much the concept of this plugin and sure be very useful.
Let us know, if our problems come from some setup mistakes we do or misunderstanding from our part, or if these errors that come out need code corrections.
Thanks for your answers.