How can I tell my boss that the informational inaccuracies aren't my
fault without sounding whiny?
I don't think you can. Your boss expects you to get this report done and done well. So any reason you give for why "you" couldn't get it done will sound like an excuse to her.
I think the best solution for you is to be proactive in getting every one else to get their info in on time.
Your Boss is holding you responsible for the report. If you want her to see you positively, you need to accept that responsibility. Remember if she has given you the responsibility for it that also means she has given you the authority to do it too.
My suggestion is to make sure that the other people make their entries on time. If they don't have the entries in, do not run the report but rather call your boss and let her know what is going on. To be clear you should not report on the data as you have been told specifically not to. But you should make sure every one gets their entries in on time.
Bringing up a problem with other people not doing their work before
the due date is far less likely to be seen as an excuse. Bringing it
up after the due date will almost certainly be seen as an excuse.
Here is an example plan for making sure all goes smoothly with the report. You may need to modify the details some.
Find out who all needs to make entries for the report and get their contact info.
Contact them (in person if you can) and ask them to have their entry done by x/x/x date. Tell them It's really important to
Send them reminder emails or phone calls when the due date approaches.
Send them reminder emails or phone calls on the due date.
After your due date for the entries to be done (but before the actual due date of the report) call your boss and tell her who has not finished their entries yet. Ask for her advice on how to get the truant employees to finish them.
Make sure the due date to have entries in by, is before your due date for the report. This way you can inform your boss about those who are not putting in the info on time the day before you have to turn in the report.
Under point number 2 since you are probably not these peoples manager it will be important to mention that you are on your bosses errand.
You may consider calling your boss to apologize for not doing the report well enough in the past and present your plan for how you are going to get the report done well in the future. Doing this lets her know that you are no being proactive in trying to improve your performance.
As a side note. I suspect that it makes your boss look bad every time you send out a report with missing data, and she is passing that discomfort on to you. That's normal behavior for humans in authority.
So from the comments @Anoplexian clarified for me that the people who are adding entries for this report are higher than her boss in the hierarchy. Obviously this changes the "plan" Because you can no long claim your bosses authority to get them to fill in their data. instead you have to make everything a request and be extra careful not to step on their toes.
Honestly this is starting to sound like a toxic work environment. Your Boss should not be blaming you for you (and her) higher ups not doing their jobs.
What I would suggest doing is writing down a plan similar to the one I outlined above. Then ask your boss for a meeting. say somthing like this:
I've been unable to run report xyz properly, and I want to make sure I do it correctly the in the future. I've made a plan for how I can do it correctly and would appreciate your feedback on this plan?
Keep the meeting short. (Tell her you will keep it short under 15 minutes).
Your presentation in the meeting should go something like this.
1) I'm sorry This has not been done well in the past.
Note that you don't have to appologize for "your" not doing it well just that it wasn't done well.
2) I have a plan to fix this
3) The problem is: Person A, person B and person C are not filling in their entries on time. And they are my superiors so I don't really have the authority to set due dates for them to get their entries made.
Be sure to emphasize that "you don't have authority" not that "personA,b,c don't fill n their data" since if you put to much emphasis on the other people not doing their job it is more likely to sound like an excuse. But it is still true and needs to be part of the discussion.
(4) We as a company should implement the following policy and give some one the authority to insure the due dates are met.
present your version of the plan given above in this question and then tell your boss. I would be happy to take responsibility or the due date (though it doesn't have to be me), so long as it is clearly communicated to person A,B, and C that I am responsible for making sure those due dates are met. Because I don't want to step on anyone's toes or overstep my bounds.
Hopefully your boss reacts well to your proactively suggesting a policy change and will help you get it implemented.
If proactively offering a solution doesn't help then you need to document that you proactively offered a solution, and document every time that the other entries are not made on time (if that's even possible) This way if you get in trouble again you can say I've tried to fix this. What else would you have me do?
I know I already said good luck but seriously your going to need it.