problems with DI-1100

problems with DI-1100

well, i have 2 devices di-1100, and i work with it at same time for data acquisition in a program in C#, and work fine, i create two extensions to work one for each one, but the problem is when stop it, sometimes stop it well, but sometimes the devices don't go out of the state of acquisition, and the message of DataqSdk1_ControlError appears when i start again my program, in the last version of the forum someone told me, that i need to restart the computer for erase the memory, and i does, but i don't want to restart the computer every time that it happen, you can help me with it.