Do you have any voip configuration so far? Because if you don't, for creating a simple serial DS0 group, you shouldn't need DSPs. At least I never recall using them years ago until establishing a voice configuration on the router!
What SW version are you using?
Do you have a VIC card, or a WIC? That may be your issue as well. With a WIC, you won't have that issue.
You must have DSPs installed in a 28xx/29xx/38xx/39xx to configure a Voice-T1/E1. The Controller/DS0-Group will not come up if you don't have the DSPs free for allocation. For lab-testing purposes you could build a smaller group like 8 channels if you have not enough for all B-channels but you must have DSPs. In the moment you bring that group up, the router grabs the amount needed from the pool of DSPs and allocate them for good. After allocating these you cannot use them for anything else anymore. You need spare DSPs if you want to continue with the Voice-configs like transcoding or conferencing. There are a few exceptions in which you do not need the HW-DSPs and the IOS can do some of the tasks related to MTPs but this is not the case for any channelized T1/E1. Use the "show inventory" command to see what is installed in your router.
No -- no config on it. I installed a VWIC T1 card on a 2811 so I'm not sure why I'm getting this message. Even after configuring only 2 chanels with this command I still get "DSP error" message. Says I have 0 resources available.
I'l check when I get back home what my "sh inv" is. Right now messing with CCNA Voice labs but eventually I want to get this lab to a CCNP Voice level so I MAY have to buy (rather not as I know it can get pricy).
Here we go guys -- looks pretty bare... looks like I have no DSPs on this guy.
NAME: "2811 chassis", DESCR: "2811 chassis"
PID: CISCO2811 , VID: V05 , SN: FTX1227A239
NAME: "Two port T1 voice interface daughtercard with Drop and Insert on Slot 0 SubSlot 2", DESCR: "Two port T1 voice interface daughtercard with Drop and Insert"
PID: VWIC-2MFT-T1-DI= , VID: 1.0, SN: 29234100