Hi Ribster
The changelog of the versions can be seen at
http://www.limewire.com/english/cont..._history.shtml That should help you decide.
As you can see, 4.1.5 has already fixed many bugs, and installing a newer version is very easy.
Re the internal errors, your LW preferences are set to "review first". If you go to Preferences->Bug Reports" you can set the option to "discard immediately" and then you will not be bombarded with the many internal errors. (they'll still happen, but LW won't bother throwing up the dialog box that allows you to look over the report first). If you want to know more about what is triggering the bug/internal error you'll have to copy the first 10 lines or so of one of those reports.