To queer the pitch means to spoil a plan, in much the same way as when a pitch is made unplayable if ruined by somebody.
1. Shantala realized the pitch was queered when the party decorations did not come on time.
2. Due to some bad maintenance work of the stadium, the pitch was queered and the baseball game could not be held at the venue.
3. The film reels were slowly gathering dust and their neglect would surely queer the pitch for the proposed film festival.