This is incorrect grammar; 帮忙 must be preceded by 我, otherwise 帮助 should be used.
I think it's OK without 我--at least for Mandarin as spoken in Taiwan.
I've never heard of this rule, can a native confirm this? Please? :)
I worked 6 months in a hotel in China, everybody says exactly 需要帮忙吗？when asking guests if they need assistance.
Both can be used as nouns (without 我 preceding as a subject), but when used as nouns 帮助 is more formal than 帮忙.
why not use 你需要帮助吗？
Yes what's the difference between 帮助 and 帮忙?
Why not "你需要什么帮助吗？"