I hope the committee will please allow my professor's recommendation to be included in my application. His university decided to do a software upgrade that has essentially crashed their system, including his computer. As such, he was unable all of last week and the week before to submit his letter, but he assures me that it will be forthcoming very soon, in paper form if no electronic solution can be found. Thank you for your consideration.
Robert, the applicant
P.S.: No, I wasn't quite that eloquent in the actual letter I sent, but I did try to get that point across. After all, what else can I do when an esteemed professor has a crash that threatens my application?