(Not a Teacher)
This my personal take on it. The first sentence sounds better as the second. Also, I would try to avoid putting any sort of emphasis on being unable to get a hold of him. It can easily sound like your exasperated by the man's chronic unavailability, which will come across as a bit rude.
I was wondering if I could borrow your DVD player to watch the movie you mentioned in class, 'Skokie'.
I've tried to get a hold of you at your office a few times, but with no luck.
You can find me at the El Camino building, Rm. 402. Much appreciated, thanks.