Mint 14 is a Release Candidate. Meaning it is still under development but stable enough to have it released as a pre-release version. While it is still under development, every bug found by the development team will get a fix and this fix will be released as an update. Untill 99% of all bugs are cleared Mint 14 will be released as an official edition.
Shortly, you are running a testversion and with this you may get a lot of updates/patches/bugfixes.
ASUS P5KPL-AM SE*Intel Core2 Quad CPU Q8200*4 GiB ram*nVidia GeForce 9500GT*Realtek RTL8101/8102E*RaLink RT2500 802.11g*Optiarc DVD-RW AD-7200A*HDD:Samsung HD501LJ/HD103SI*Sitecom X5-N600 Router*Mint 15
Thanks - I suppose you're right - the Ubuntu base on which the distribution release was built must be a little bit out of date.
I have installed the latest Virtualbox from the deb file (the repo version is old) and installed XP in Virtualbox (to run some essential Windows software) - not a glitch - this is looking great so far.