Rekordbox DJ Freeze

Hello.

Using Rekordbox DJ 4.2.5 with 2x PLX500 DVS into the DJM450 Mixer.  Computer is a Dell Precision m6600 windows 7 pro, i7 2.2ghz 64bit, 8gb ram.

playing a song and I hit the memory/hotcue 1 button (with nothing in the memory bank) the software play back halts.

I switch to internal mode, and I cannot get the music to play again.  I have to quit the software and reopen it.

I am testing this, so I can switch over from another software.  I cannot have these sorts of drops.  Is there a check list to ensure setup is complete?