It's possible that the decompiled file is bad. Try Valve's version: Left 4 Dead 2\sdk_content\Starter_Kits\Survivors\L4D2\Nick\models\survivors\Compiling Files\dmx\animation\c4m1_intro_gambler.dmx

Good spot Zeq. This actually appears to be a bug in Python! It ought to throw an exception when given a path containing a colon.

Exporting worked for me because I grouped the objects together and didn't put a colon in the group name. I should have tried exporting an object individually, then I would have immediately reproduced the problem.

To rename things en masse you can use the Python Console. Do this:

Hit Window > Toggle System Console, export, and paste the results here.

This scene doesn't have an export path set so won't export any files at all. Were you not seeing an error about that whenever you tried to export?

Regardless, I grouped all the objects together (in order to output everything to a single file) and it exports successfully. The file weighs in at 38MB.

Do a Save As in Blender, then check the "Compress" box.

Hello again. Use this site: http://www.pasteall.org/blend/

As long as you're not in edit mode, that should be it.

Are you trying to import a decompiled animation or the file provided in the L4D2 authoring tools?

Nothing happens in that animation until frame 80. Try skipping there.

Please be specific. What steps are you performing, and what is happening when you perform them?

No, you can't currently import SFM facial animation. I believe someone is working on a script to make that happen.

You can import the underlying flex shapes.