If my husband and I signed the wrong version of a prenup that was not what we had agreed upon, is it valid?

If your husband also agrees that this was the wrong version, it may be voided: a contract (and that's what a pre-nup is: a contract) may be voided for "mutual mistake"--i.e. for the parties getting a version of the contract which doesnt' reflect what they *mutually* had agreed to.
However, if your husband is fine with what he signed and you are the only one who feels there was an error, you can only void the agreement if there was "fraud": that is, if your husband knowingly lied to you about the contents of the agreement to get ou to sign it and you *reasonably* relied on what he said. That is because the law requires people to read and understand what they sign, so if one person did but the other didn't, the one who didn't is held to the agreement in the absence of fraud or deceit. And note: even if your husband did lie, if you had an attorney and he advised against signing, then your reliance on what your husband said may well not be reasonable--you had legal advice to not sign--and if the reliance on the fraudulent statements etc. was not reasonable, then legally, the lie was not "fraud" because you had good reason to ignore it. So the fact that your lawyer advised you to not sign probably means you would be bound to the agreement, unless your husband also agrees that the pre-nup is wrong.