Most business presentations in the world are written in English, most people who write them are not native English speakers. Different type of errors pop up:

1. Typos and grammatical errors that can be caught by a spell checker / other software

2. Typos and grammatical errors that are hard to spot by software

3. Mistakes in word choices, a literal translation from another language into English produces a result with a totally different meaning, or double meaning in slang

Number 1 can be avoided, no excuse here.

Number 2 are also made by native English speaker, they look sloppy but are not a deal breaker. To catch all of them, you might need to help of a professional editor.

Number 3 can be a big problem and really damage the credibility of your presentation. Having your presentation read by anyone who is an English speaker will catch these, also no excuses here.