One of the most powerful utility that comes with eXtreme Movie Manager is the Script's EDITOR. This software can really help you in writing your own Script because it can Analyze, Execute step by step and Debug you work. You can also set "Breakpoints" to stop execution in a particular line, watch the values of the variables at any time and check in the Import Window directly the data.
There is a complete help for using it, please refer directly to the Editor.

Note that the Editor that comes with releases >1.0 is only for Scripts of SECOND GENERATION, and that can't handle the old one. For this, you must download an older version of DM (for example the 0.9). If you try to execute an old script here, probably you will receive tons of "Script's errors" by Engine.