Mdworker process stuck at 100% CPU utilization

Hi!

I just got myself a new iMac 27 (680mx, 16gb ram, 768gb SSD), and I'm very happy with the machine. However, there is one annoying issue. I have the latest version of Mountain Lion, and after a few days the mdworker process started to hang several times a day, getting stuck at 100%. The only way to stop this is to boot OSX in safe mode.

Is there any way to permanently fix this issue?
When I go through the mdworker error messages in Console, I get these messages A LOT every day:

(There are several others, but these are the most frequent ones I see in my Console right now.)

I would really appreciate any help, I'm completely stuck here.
Thanks.

1:

1/26/13 1:58:22.697 PM mdworker[554]: Unable to talk to lsboxd

2:

1/26/13 2:00:23.459 PM sandboxd[560]: ([559]) mdworker(559) deny mach-lookup com.apple.ls.boxd

3:

1/26/13 12:28:40.935 AM sandboxd[627]: ([626]) mdworker32(626) deny file-write-create /Users/James/Library/Application Support/Sibelius Software/Temp (import fstype:hfs fsflag:480D000 flags:40000005E diag:0 uti:com.sibelius.score plugin:/Sibelius 6.app/Contents/Library/Spotlight/SibeliusScore.mdimporter - find suspect file using: sudo mdutil -t 1321224)