There are too many reason can cause this error. But the major reason is that jvm can only very little memory. For some phones it's 1M bytes some other phones have the default of 2M bytes. For motorola phones there is a way to change this: http://www.teesoft.info/content/view/26/35/ if you know the way to change the java heap size for other phones please let us know, thanks.

 Other then modify the java setting, there are also some other ways to avoid this:

1. Use the desktop version of jStarDict to split the large files to small ones. The mothod is to add the dict to jStarDict in your  pc, then export  dict with split large files on. Then copy the exported dicts to your phone. The default split setting should work for most dict. You can make the final file size even little if it not work.

2. If you don't want to  split the files, at least you need to uncompress the dict.dz files. It will help too.

3. Enable only the needed dicts.