The Open Tray error has absolutely NOTHING to do with which firmware version you're using.
I bought a ten-pack of Verbatim DVD+R DLs and burnt seven bad discs all with varying firmware. Each bad burn would try and read for about ten seconds on my Hitachi v59DJ before offering me the option to Open Tray.
I tried the last three firmware revisions, including v1.23 and v1.29.
After reading this thread
http://www.xboxhacker.net/forums/index.php?topic=3890.0 (read every post, including GaryOPA's) I bought a twenty-pack and started burning with IMGBurn at 4x instead of 2.4x, making ABSOLUTELY CERTAIN that NOTHING else was going on in the background of my system and since then I have burnt six flawless discs. With v1.29 firmware.
I repeat: the source of the problem is burning at 2.4x and possibly having programs running in the background during the lead-in/lead-out portion of the burning. Burn at 4x and make sure nothing else is running and your problem should be solved.
It also has something to do with the drive /laser because all my back ups play fine on a different drive.