If you look at your <left square bracket>post: // 57396|list<right square bracket> of WeeCodes, (or the raw text of this link) you'll see the pipe after "post: // 57396" to delimit the link text. This currently works for post, http, gogle, news, usenet and defn protocols. It is not implemented on twiki or user protocols.
Where it was breaking: I turned off all the processing (new line, html, url and WeeCode) and it was still breaking. I tried indicating the brackets, and it still broke. Then I added spaces before and after slashes in the first link, no luck. Then added spaces before and after slashes in the second link, where I quoted "post: // 577396" and it works. Copied the text above into the test forum, turned indicated brackets back into actual brackets, delteted spaces around slashes, and got the same error.