Myself and others have been saving to AVI files the video and data on our robots. Occasionally something happens to interrupt RR - like the power being turned off - and the files are not closed properly. I managed to edit the files so they can be viewed. Sometimes the file has important information about what happened to the robot.
You need a editor that will edit a binary file and the program DivFix++. I used Visual Studio's editor.
The problem is the header for the AVI is not written so media players do not recognize it as an AVI file. The header needs to be put properly onto the file.
Open a good AVI file in the editor that used the same recording format as your bad file. Copy the first 0x800 (800 in hex bytes) from the good file. This data is from the beginning to where you will see LISTJ...movi. The value 00db appears at byte 0x800. You will see this in the bad file, also, but everything before it is zeros.
Paste the data from the good file into the bad file replacing the bytes in the bad file. Save the bad file using a different file name so if you did not get it correct you can start over.
Load the fixed file into DivFix and tell it to fix the errors. DivFix will work through the fixed file and determine the proper information, file lengths and maybe other data, to put into the header. Tell DivFix to save it. It will create another file with a new name.
If that does not work I cannot help you and something else must be wrong with your fils.