I've heard some suggestion that forwarding of domain names is bad for SEO.

Let's say hypothetically my primary domain is saltychocolateballs.com, but I'm afraid that many people will mistype the domain and try to visit saltychocolateball.com instead. If they try to visit the 2nd domain, they will get a "file not found" error and may figure that we don't exist. Forwarding seems to be an easy solution.

Is there any possibility that google (or any other search engine) would penalize my primary domain name, if I have my registrar automatically forward the 2nd domain to the primary domain name? Just to clarify, I don't want the 2nd domain to get indexed by the search engines, I just don't want to lose traffic from people typing in the domain incorrectly.

Alternatively...would it be better to forward to an internal page on my primary site, saying: "you typed saltychocolateball.com but probably meant to type saltychocolateballs.com, click here to go to the homepage."