As for the potential for reception problems that I mentioned above, if you don't have a good clean signal you will have trouble decoding the digital talkgroups from time to time.
1. Signal strength
Make sure and orient your scanner so that it provides you with the best signal strength possible.
2. Local interference
Sometimes you may have your scanner near computers or other electronic devices that can induce local interference on top of an otherwise good signal. Try to keep your scanner away from devices that may induce local interference.
3. Multipath Distortion (sometimes called Simulcast Distortion)
The Canton/Stark Co system is a simulcast system -- there are many sites, but they all use the same exact frequencies and transmit simultaneously on the same frequency when there is voice activity on the system. This can cause problems, especially for digital reception, if you are receiving signals from multiple sites at / near the same signal strength. The "bits" of information that are transmitted in a digital transmission are time sensitive, and depending slight variances in the time it takes for that information to make it to your scanner receiver [depending upon the transmitter sites you are hearing] can cause the digital bits to appear as a jumbled mess to your receiver. This in turn can cause your receiver to have difficulty decoding the digital signal.
I can't guarantee that this is your problem. I think in general people in Stark Co have few problems with this phenomenon. But it is possible that this is happening to you. Multipath Distortion isn't nearly as problematic on analog talkgroups since your ears are pretty good about copying analog audio even in the presence of multipath.
At any rate, take care of your TSYS object parameters before you do anything else.
Mike