256 MB is not a lot of ram for running LW in OSX. Both Java & LW have a bit of an issue with ram & virtual memory (memory stored on the HDD.)

May I recommend you try to reduce the amount of ram LW uses by doing these things:
1. Close any LW windows you don't need open such as the monitor & even the Library window. (I only keep the search-dwnld window open unless I want to check one of the others, & then close it when I'm finished with it.)
2. When a search has obviously become redundant b/c it's many hrs old (yes they become a bit stale after a while), close that search result.
3. Go to LW's Prefs>Downloads & select Auto-clear completed Dwnlds & tick this option, & then pres the Apply button.
4. Don't run too many other apps at the same time as LW!!!
5. Make sure you still have plenty of space on your HDD.

You can monitor how much RAM & how much virtual memory (VM) LW is using & how much HDD space you still have left by opening up the Activity Monitor found in your Utilities folder.

Other things you should do are (A) Restart your computer doing a SAFE start (hold down the SHIFT key when you restart) & then open the Disk Utility program found in your Utilities folder & Repair your OSX. This should be done both before & after you install any softw. See Permissions
(B) Install Java using the Standalone Java installer (click on link)

With any luck things will improve from here!