tripped up on the last question

H-P Trips on Weak PC Sales

H-P's quarterly profit jumped 16% on strong demand from commercial customers but sales declined in two of its biggest businesses: PCs and technology services. Shares slumped.

trip

v., tripped, trip·ping, trips. v.intr.

1. To stumble.
2. To move nimbly with light rapid steps; skip.
3. To be released, as a tooth on an escapement wheel in a watch.
4. To make a trip.
5. To make a mistake: tripped up on the last question.
6. Slang. To have a drug-induced hallucination.