question about gtk-builder

[Juan Cardelino <juan cardelino gmail com>]

Hello everyone,

I have an old glade interface that I'm trying to convert to glade-3.
I've converted the .glade file to a .xml one with gtk-builder-convert,
and made a sample C program using GtkBuilder and was able to
succesfully run my interface. I read the xml file like this:

   if (gtk_builder_add_from_file (builder, "pepe.xml", &err) == 0)
   {
      fprintf(stderr,"error: %s\n",err->message);
      return(1);
   }

And everything works fine. However, my real application is a plugin
for another program, meaning that I'm embedding this code in a shared
library. So when I make the same call the library I get this error:
error: Invalid object type `GtkWindow'

Are there any ways (programatically) to check the versions of the files?
I'm completely new about GtkBuilder and Glade in general, so any help
would be appreciated.
Thanks in advance.
Best regards,
                      Juan