Presuming that the IR codes for the 0~9 numbers are captured correctly, then problems like this are usually down to either insufficient time between key presses, which can be solved by adding a small macro delay to each key; or the device being controlled is receiving multiple IR streams either directly from the hand unit and the IR emitters, or there's a blaster in the cabinet that's bouncing IR in multiple paths.

Did you have the system installed professionally or is this a DIY job?