I have a similar problem but I think you may have a PC and I have a mac, but I still can't open the dmg.

(I'm new here and have read loads of threads, so I hope this is where I am supposed to post a reply. )

My limewire dmg downloads, but when I double click on it I can't open it.
I have plenty of space, infact here are all the answers to all the questions I found on other threads. I hope someone can help both of us.

When I couldn't open the dmg, I deleted it, emptied the trash did disk utility repair, restarted computer.

Went to the OSX Firewall instructions posted by Lord of the Rings, downloaded the Java 5.0 but I couldn't load it as the hard disk had a red exclamation mark. Rechecked and I had already an updated version.
I then downloaded limewire once again - this time when I double clicked on the dmg I got the message "not recognised" !
Have no idea where to go from here.
Hope someone out there has an idea for me.
Thanks in advance
Matilda

These are the answers to the questions.

Mac OSX 10.4.8
Only firewall ticked is Gnutella/Limewire
768 MB DDR SDRAM
18.11 GB available HD space
Broadband
Linksys ADSL Gateway AG041- UPnP is enabled. Administration port is 8080
This model isn't listed in the link Grandpa listed.
Connecting from home
Trying to open latest version of Limewire - doesn't get recognised
Java 1.4.2 plugin setting
Java 1.3.1 plugin setting
Java15 release 1. dmg - can't install
Internode is my service provider
it says "your test worked"
Not sharing with other computers
New problem, an experienced user using other versions of limewire now deleted
yes I saw the blue brick wall
I don't have any anti-spyware, or ant- virus programs