Is the value in some other table? If so it's very odd that you'd want to copy it to another table or field and even more odd that you'd want to get it from a report?
To get to your point, it could be because you're using the report close event for this, but I'm not real confident of that. Reports are weird in that they seem to behave the opposite way than forms do. Reports close first, then unload. You could try putting a breakpoint at the start of the code, attempt to close the report and step thru with F8 to see if it makes a difference. If it does, it could be a timing issue.
BTW, what does "does not work" mean?
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.