Upload Problems: Let's Get Solution!

Folks,
I've scoured the forums about this problem, but have not found the a solution yet.

Here's my problem. Noone can upload files from me. I have 150+ MP3s which get a lot of hits, but noone seems to try and download these files.

I'm sitting behing a router and am using MAC OS 10.2 and the newest version of limewire (2.7 I think). Here is what I have tried:

1. Forward ports to my local IP address - I actually forwarded a large range with no success.

2. I clicked the 'Force Local IP' option and put in my 'wan' IP address (the IP of the router). This did not help.

3. I then put my computer out on the internet as the 'DMZ Host' on my router. This did not work either.

I have heard that potentially my cable modem provider could be blocking ports to prevent uploads from occuring. That may be the case, but I should be able to change the port settings in Limewire and it should work. I tried that once, and it did not. Tonight I will try other ports to see what happens.

Assuming that this does not work - is there anything else that I should try? I imagine that a lot of other people have had this problem, but I haven't been able to find an answer that has helped me yet.
TIA