Your picture is very blurry. But, having Cydia throw errors is not unknown. The best thing to do is to fully close Cydia (via the multi-task bar) and then try again. If that didn't help, again fully close Cydia and try again after waiting a while.
If that doesn't work, do a restart or a reset on your iPad and see if that helps.
Sometimes, it's just Cydia "acting up." So, try the above and, if nothing helped, holler back and we'll try again.
Marilyn