Python script split up

My question is pretty simple:

I have a python script which works with Grass 6.4. At some point during the project I decided to split this big python script into several scripts. I have made all necessary variables global, created methods, imported scripts in other scripts, etc.

The problem now is that during execution, I get an error on importing grass. More specifically, on "import grass.script as grass". This happens in any of the new scripts that have the import line. The strange thing is that I had the same import line in the old script (the big one) and it never failed.

Anyone has any ideas? Is there anything I am missing here?