I have to translate the sentence from the services agreement.

I have to translate the sentence: "IN NO EVENT WILL EITHER PARTY BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES UNDER ANY FORM OR THEORY OF ACTION WHATSOEVER". What does it mean: DAMAGES UNDER ANY FORM OR THEORY OF ACTION WHATSOEVER? I need some help!

IN NO EVENT WILL EITHER PARTY BE LIABLE FOR = No one is liable for Damages, no matter what happens

No one is liable for [Indirect, Special, ... Consequential] Damages [Under ...] Action I guess means Legal Action

whatsoever = whatever, all, any, every

I have to translate the sentence from a service agreement.

I have to translate the sentence: "IN NO EVENT WILL EITHER PARTY BE LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES UNDER ANY FORM OR THEORY OF ACTION WHATSOEVER". What does it mean: DAMAGES UNDER ANY FORM OR THEORY OF ACTION WHATSOEVER? I need some help!

An "action" is usually a lawsuit brought in a court, a судебный процесс.  There are different "forms" of lawsuit.  For examples, some lawsuits are brought by private parties (частные личности).  Others are brought in courts by governmental agencies.  Another "form" of an action is an administrative hearing; that is, a proceeding which does not take place in a court, but in an administrative agency.  (административное право).  Still another "form" of an action is an arbitration.   No matter what "form" the action takes, the disclaimer (отказ от ответсвенности) means that the plaintiff will not be able to recover the types of damages specified.

Furthermore, there often exists more than one theory upon which to sue.  For example, you enter into a contract pursuant to which you will purchase "a machine in good working order".  You buy the machine, and when you are using it, the machine explodes and injures you.  In such a case, you could sue on the theory of breach of contract, because the machine did not conform to the contract ("a macine in good working order.")  However, you could also sue on a theory of negligence, and attempt to show that the machine was carelessly constructed.  Under the disclaimer, you could not recover the specified types of damages, regardless of which theory you sue under.

So, the phrase you ask about means that wherever and however you sue, and whatever theory you assert in court, you will not be able to recover indirect, special, incidental, or consequential damages.