It means that Bob's personal skills failed to meet the required level . The context here is presumably a conversation between people who have just interviewed him for a job. The speaker feels that Bob's personal skills weren't of a sufficiently high standard. The word 'short' is very often to mean lacking or insufficient - for example 'We're short of money'. NB Please remember always to use the full form of pronouns. The correct word is 'you' not 'u'. 'U' is not acceptable outside of text messages. And even within text messages, most native speakers stopped using this irritating form about 10 years ago.