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Open Cydia, remove the last package you installed.

What was the last thing you did before you start having this issue? if you give us more details we can try to point you to a solution.
 
Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_0_1 like Mac OS X; en-us) AppleWebKit/532.9 (KHTML, like Gecko) Version/4.0.5 Mobile/8A306 Safari/6531.22.7)

Just installed quick reply but I restarted and it works fine now. Everything works great again.
 
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