MPC1000 - Sequence question

I have a MPC since 2 months now so I'm a real noobie.....

Yesterday I chopped a 14 second sample into 12 slices.
From these 12 I want to use 1 kick, 2 different snares and 3 melodies.
I made a new sequence and on track1 i layed down the melodie.
When i wanted to lay down the kick on track2 (overdub) the pads did not respond.
When there is a silence in the sequence (and no melodie is played) the pad responds again or when I repeatedly tab the kick pad sometimes the kick get's recorded and the melody is being deleted at that point.

I tried to do it the other way, record kick first then melody but then I got the same problem.
I turned the mpc of, started it again but same problem.

Can anybody lead me to a solution?

yes, you have to set the program mode to poly, now it's in mono (samples wont overlap).

thanks m:t:c !
Gonna try it when I get home today.....

i checked if the program mode was on poly and it was so i tried to lay down a sequence again and i had no problems laying down the kicks over the melody samples....

i dont understand what the problem was....

More strange things:

* When I'm using the MPC it suddenly hangs, nothing reacts no more only way out is to turn the mpc of.

* When I browse to a folder on the hard disk, the hard disk is suddenly empty and i cant find anything on it except empty folders, when i turn my mpc of and on again the folder ain't empty no more but when start to browse again the same problem starts again.

will an update to the JJ OS be the solution for all this?

so you're using akai os?

My suggestion here:
*backup your stuff from the hard drive
*try JJ OS 1 (the free version or the final gold)
*format the hard drive with JJ OS 1
*hopefully solved all problems for good

i installed jj-os v3.08...hopefully the problems wont come back now....