American and Argentine officials said there was no evidence suggesting terrorism.
Argentine officials argue, on the other hand, that they have done many of the things the fund has demanded, often over strong internal opposition.
The snag has led Argentine and American officials to doubt that anything will be done.
Argentine officials had made clear they were seeking up to $9 billion in new loans.
Argentine officials hope the deal they are trying to work out with local banks and pension funds could serve as a model for future swaps.
Argentine officials acknowledge that fresh lending in 2002 is almost out of the question.
A senior Argentine official said the ideas were welcome but questioned whether the changes "are going to be enough or in time."
Argentine officials did not immediately release the terms of the new agreement, including the exact amount to be restructured.
On location filming at the school where the tragedy occurred was blocked by Argentine officials.
Arregui was known to have met with Argentine officials in June.