Whatever version of libCURL you linked against isn't redirecting to the correct URL. Use the correct URL in the arguments instead and it should work.
./rpcminer -url=http://mining.bitcoin.cz:8332/ -user=user.1 -pass=pass
I compiled with curl 7.21.2 and appended the "/" on the end of the url and got the same result, 0 khash/s
Also, I was able to use the command line to get a response from the server using curl.
/usr/bin/curl http://mining.bitcoin.cz:8332/ --user hidden.1:hidden
{"id": "4303f69c-3d34-11e0-a2f7-fefd6d4ac335", "result": {"hash1": "00000000000000000000000000000000000000000000000000000000000000000000008000000000000000000000000000000000000000000000000000010000", "data": "00000001c2288b009b20a375b8be48f60e5c525df8b3f2e3b8bc0cc4000113ea000000005c8569d196dc86a3aca747c8269bd385216639d82b26cf8b44f3eae5cec6ea1e4d61809a1b01cc2600000000000000800000000000000000000000000000000000000000000000000000000000000000000000000000000080020000", "midstate": "7c2c459ae8eae7e09b4db01685665b7cbb970ba14d7256227d09f8194dd10b2c", "target": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffff00000000"}, "error": null}