Oy vey. I had a situation at work this past week where I was asked to handle the requests of auditors who were reviewing the files of a former coworker who quit two weeks ago. I was supposed to locate contract documents in randomly-selected clients' files and provide them to the auditors, on the behalf my boss, who was in the hospital with his sick wife.
As it turns out, this former coworker really had let things slide before leaving and one of the contracts was nowhere to be found, so I was instructed my my boss to 'recreate' the document, including having another coworker drive out to the clients' home to have her POA sign another copy, then fudge the dates on it. Although I was instructed by management to do this, like you, I was still having visions of being fired and ending up in jail, etc. (The contract was for a state-funded project). As in your situation, there is no email trail for these instructions, they were given to me by phone, although I do have coworker witnesses, at least.
This week, I have an audit coming up on my files for my own program, but at least that is something I am feeling pretty prepared for and is not something being dumped on me that is totally outside of my locus of control. I think it's the whole fear of being held responsible for things you have limited-to-no control over part that is probably the worst factor for both of us. But, yeah, anyhow, if it makes you feel better, it's not any more fun for the people you are auditing and there is plenty of stress and frustration to go around. 