
It depends on the mode you're using.  For a single 64-bit input block, a
one-bit error will have a 50 percent chance of corrupting each of the 64
output bits - in other words, it essentially turns the output block into
a random number.  If you're encrypting data in CBC mode, however, only the
one 64-bit block will be affected.  The next block, and all that follow it
will be decrypted properly.

It's a good idea to have some kind of error correction in your system if
corrupted bits are likely.