This applies to everything from the institution's mission and future direction to its name. I've seen candidates who misspell the institution's name in their cover letter and mispronounce it in their interview. Before the search committee meets you in person, they meet you on paper. It's a big mistake to send a cover letter in which the position referred to is not the position you're applying for. Committees may understand the perils of word processing, but they may not be sympathetic.
Spelling errors are similarly unacceptable.
Missing dates for key events are irritating, and incorrect dates may be read as an effort to deceive. These excesses are interpreted as a reflection of the writer's inability to focus on what is important for the committee's members to know, and a lack of respect for their time. There are perils in signaling how interested you are in the position. You don't want to appear too interested or not interested enough. I've seen committees react very negatively to a candidate who appears to be campaigning for a job.