In the sentnece: I want to dance. "to dance" is an infinitive verb. Dancing is good. "Dancing" is a gerund, a gerund is a verb that is used as a noun. I like coffee = "coffee" is a noun. I like dancing = "dancing" is a gerund (a verb used as a noun). I was immune to evil = "evil" is a noun. I was immune to needing = "needing" is a gerund (a verb used as a noun). The verb "to help" can be used without "to" before an infitive, I can help you get there. She helps me resolve my problems. Who wants to help her bring the books? I hope this helps you.

For your first question, as the rest has answered, "needing" is a gerund (verbs that are used as nouns) in this case. In your sentence, the gerund "needing" is used as an object of the preposition "to". Here are some other examples: "He doesn't care ABOUT BEING on time" (gerund "being" used as the object of the preposition "about") "She was in charge OF ORGANISING the party" (gerund "organising" used as the object of the preposition "of") Note: Not all verbs that end with -ing are gerunds. They can just be in the continuous aspect (e.g. present continuous) You will see a present continuous verb in the example below: Take note also, that the preposition "to" is not always a preposition. It can be part of an infinitive verb (i.e. to go). In the following case, "to" is part of an infinitive verb, so a gerund does not follow the verb: "I am going to take out the garbage bags" ("am going" is the present continuous tense of the verb "to go", and the verb that follows this present continuous verb must be in the infinitive form, "to take"). Hope this helps you understand more about gerunds and their use! :)

Needing is the verb in this sentence. Need is present tense. "I need this" , "I needed this" = past tense, "I am needing this" = current. For your second question, its kind of like the first one. The sentence is past tense, the vote is done. So just like "I needed this" is past, "Could of helped" is also past tense.

As Mario has said, "needing" is a gerund. If you can replace (verb)ing with another noun, then you need a gerund. Don't confuse it with "to (verb)"! :) I had always assumed I was immune to [serious illnesses]. I had always assumed I was immune to [criticism]. I had always assumed I was immune to [needing acceptance]. "Help" can be followed by "to" or not. The difference is minimal. For your own example, it should read, "I helped something happen in the world."

sorry, I was inclined to say 'infinitive'