Cheers! *Spoilers ahead*
The game intentionally rejects 'use berry on...', because a specific verb is best used there (it would accept 'throw berry...', 'use berry with...' etc). 'Use' makes text-based puzzles too easy and so unless it's for basic actions ('use diskette with computer'), I'd rather not do it that way. But it might be worth adding a special output, like 'Use...how? Be more specific.'