"Butch" is usually used in reference to females that look like males or display masculine traits. However, in this case, if used in reference to a male, it simply means very masculine looking. Yes, to "screw up" is to make a mistake. It doesn't refer to anything in particular, it just means that a mistake was made and in your case, the mistake was the fault of the receptionist. The receptionist could have input the meeting at the wrong time, could have said the wrong thing in the meeting, etc. "Screw up" has no specific meaning it just means to make a bad mistake.

Sara's answers are very accurate. I would just like to add that butch may be viewed as being very insensitive and that to many "to screw up" is very vulgar and inappropriate to use in conversation, especially for business or polite company.