@animal chin
1) about preview using mplayer:
Can you try to set up aMule to use VLC for previewing (see the Readme.Mac.txt file that comes with aMule for instructions)? Someone reported problems with using mplayer for video previewing in aMule a few weeks ago, but I did not have the time yet to systematically investigate. Personally I am using VLC and therefore I know that it definitively works with aMule.
2) Concerning the downloads that won't finish:
Is the last chunk read? Then look into the "Last seen complete" column for one of these files. If it says "Unknown", you've never seen the file complete, which would indicate that the file is dead on the network.
Another option is that you are experiencing file corruption. Check if the aMule log (same window as server list) if there are messages like the following (which would indicate corruptions):
2006-08-06 20:53:21: PartFiles: SomeFile.rar: Expected part-hash: ABCD045BB73C8A6D9B94B96A872ED20C
2006-08-06 20:53:21: PartFiles: SomeFile.rar: Actual part-hash: 59C09888EBA4D76A9F5AABBE71ED5655
The last option is that everything is going as expected but you just need to be a little more patient.
