Hi 
Crashing used to be usually due to having Java active.
Base often uses Java and so do screen-readers and such but almost
everything 'normal' users do doesn't need Java at all. It's possible to
just switch Java off in just LibreOffice before considering removing it
entirely. If it grumbles then just re-enable it.
More likely is that you maybe just need to bump up the settings in
"Memory". The default settings there are for ancient very low-spec
machines and if you have a 1Gb of ram or more then bumping up the amount of
ram that LO can use might well help quite a bit.
Tools - Options - Memory ? or Advanced?
Of course crashing could also be a hardware issue such as wobbly
graphics-card that just needs to be pushed in a bit more firmly (while the
computer is off, of course!) - or perhaps damaged ram or hard-drive. These
sorts of things are fairly unlikely in your case i would think and the
simpler answers are worth trying before worrying about any of that stuff.
Trying the PPA is an excellent idea of course.
Regards form
Tom 