My reading would be this: "We found some new emails. They're relevant, but we don't know if they're important. We're looking into it."
What I find interesting is the timing of this letter and, possibly, the fact that he wrote it at all. But we can't judge the significance of those without knowing if this is standard procedure. For all we know, he may regularly send letters that say things like "I spelled a word wrong on page 875 of our report. Agents are looking into correcting it and resubmitting the report."
Or this type of letter could be highly unusual, especially days before a presidential election.
Either way, he had to know Chaffetz would be shouting this from the top of a mountain...