I thought I'd throw this out to help people as they submit errata--following a few simple guidelines can make it easier for us to take what you submit and incorporate it into errata documents and future reprints.
There generally are three kinds of errata, which I'll classify as typos, canon errors, and rules errors. "Typos" is a broad swath that can incorporate misspellings of words, missing page numbers, layout issues, etc. The errors with typos are usually clear--you see the word "taht" on a page, and you think "I'm pretty sure that's not a word, and it should be spelled 'that'," and that's that! For typo errata, a page reference (and, even better, a column-and-paragraph reference) of where the problem is can help us zero in and list the correction.
Canon errata is a little more complicated. This is errata stating that something in a product conflicts with previously published information. It can be complicated by the fact that the Sixth World is always evolving, plus there are parts of it that are subject to interpretation. When posting a canon error, then, it's best to be as specific as possible. Describe the error, then provide a page reference to an already-published source that demonstrates how the new source is in error. Canon errata that starts out by saying "I can't remember what book this is in, but I'm pretty sure at one point . . ." is of the less-helpful variety.
Rules errors can cover a wide range of things, from rules that are stated differently in different locations to rules that seem in conflict with each other. Usually errata is for strictly fact-based errors--for example, if a new product stated that the modifier for firing an unmounted gun in a moving vehicle was –2, an errata note would point out that p. 150 of SR4A (once again, page references are enormously helpful!) says that that modifier should be –3.
Errata can be used to correct a rule that is broken, but notes need to be very clear on how the rule simply doesn't work in the context of existing rules. Sometimes a rule is referred to as "broken" when perhaps it is just cumbersome, or something a player doesn't like. We don't want rules to be cumbersome, of course, but errata generally is not the place to address such issues. Or else we'd get into debates about which rules are "cumbersome" and which are not, and how to fix them, and then heaven help us all once we get to that point.
I appreciate the willingness of people to post corrections so that we can compile official errata!
Jason H.
Edited to incorporate errata!