"Is there a General Release Form from Legal Claims by beneficiaries for an Executor of a Will? If so, is the form specific for each State? Where can I obtain form?"
Yes such a form, or some variation, is commonly used. The executor (personal administrator) should always have beneficiaires sign a document stating that they understand what they are entitled to, they received it, they release and hold harmless the executor (i.e., they won't sue). Some releases are combined with a beneficiaries promise to return the bequest if its needed to pay taxes or other expenses (called a Release and Refunding Bond). In some instances the Release may be combined with, or just associated with, an accounting (a formal calculation of what is in the estate and what the beneficiary is entitled to). The documents are fact and state law specific in some instances, in other instances a rather general form might suffice. You really should seek guidance of a probate attorney, especially if there are estate taxes to pay or disputes between heirs.