http://www.ricoh-imaging.co.jp/english/support/digital/k-5_2_s.html
It seems that there was a major bug in the last firmware, so an urgent update is needed. The bug is not told, though. I have also seen quite some users of other Pentax models reported about strange phenomenon since the last recent updates for their bodies. So, it would be wise not to do the update if you have other newer model(s) but not yet, until the actual problem is told clearer, my humble advice!