You get the "null" message in the Apple installer when a OS X thinks a more recent version is installed. Double-click the harddrive icon, open the Library, open the Receipts folder, then find the file: Install LimeWire.pkg, delete it and try again.

Also to help stop crashing->
1. Setting up Java 1.5

2. SAFE Boot & Repair Permissions which should be done after any installations or updates.

3. Don't share more than about 1,500 files. If they are mostly video files then reduce it a little more.

4. Delete the LW prefs folder found here: /Users/your_username/Library/Preferences/LimeWire

5. Tip: Purge the Downloads Queue! (click on blue link)

6. Go to LW's preferences -> Advanced -> Performance & disable Ultrapeer capabilities & also disable TLS. Sample image