ITunes v.11.1.4.62 & Serato DJ digital DJ'ing software...

Question

Cc: Mixed In Key 6 Support;
      Platinum Notes Support;
      Serato DJ (v.1.5.2) Support;
      Numark Support (for MixDeck Quad)
I am sending this request for support to all the above companies, as I do not know where the issues I am having originate from.
Laptop hardware & software profile
Windows 7Pro, 64-bit edition
16 Gigabyte RAM
Intel i7, 8-core 3630QM @ 2.4 GHz processor
64GB SSD (for Windows) (C: drive)
1 Terabyte SATA HDD (for music) (D: drive)
I use this laptop exclusively for digital DJ’ing with Serato DJ v.1.5.2 (paid-for) software (via iTunes - v.11.1.4.62) & a Numark MixDeck Quad controller/mixer.
Description of problem
Now to try to describe the issues I have encountered –
The purpose of my chosen hard disk configuration (above) is, as far as possible, to keep my music separate from the rest of Windows, Programs, etc. (Can this actually be done?).  With this in mind, I set the iTunes Media folder location to –
‘D:\My Music\iTunes\iTunes Media’,
from the default location of –
‘C:\Users\My Username\Music\iTunes\iTunes Media’.
Having ‘ripped’ several hundred of my own CD’s – at 320kbps in MP3 format - in iTunes, I then installed Mixed In Key & Platinum Notes - on the advice of other pro-DJ’s - & analysed my music in both programs.  This maybe where my problem originates, but I am not sure.
(I think ?)  Platinum Notes creates a ‘new, improved’ version of your music files (MP3), with a ‘_pn.mp3’ suffix.  I have now deleted all ‘_pn.mp3’ files & removed Platinum Notes from the laptop.  Despite this, there are still several hundred tracks listed in Serato DJ, on the ‘Music’ tab, that show Platinum Notes in the file path despite having deleted all tracks with a ‘_pn.mp3’ suffix & removed Platinum Notes from the laptop. How can this be?
In iTunes, almost every track has an ‘!’  (exclamation mark) inside a circle in the first column & if I try to play a track a dialog box titled ‘iTunes’ pops up & says, ‘The song “[song title]” could not be used -because the original file could not be found.  Would you like to locate it?’  There are two buttons to choose from, ‘Locate’ & ‘Cancel’.  ‘Locate’ opens the aforementioned ‘D:\My Music\iTunes\iTunes Media’ folder, but the chosen track does not seem to be there.  (Incidentally, all the tracks in the ‘… \iTunes Media’ folder are in blue which, I think, means it is a copy of the original – not sure if this is important?).  Choosing ‘Cancel’ either takes me to the next Track that iTunes CAN find in the folder, or sometimes plays the Track it claims cannot be located! (these 2 actions seem to happen at random)  If the chosen Track cannot be found then the ‘!’ inside a circle appears in the first column in iTunes, despite it not being there before.
I am almost at the point of reformatting both the ‘C:’ & ‘D:’ drives & starting from scratch, but the thought of ripping 200+ CD’s again leads me to seek a better solution.
Moving onto Serato DJ –
In Setup, on the ‘Library + Display’ tab, ‘Show iTunes library’ & ‘Protect library’ are both selected.  Selecting ‘Music’ under ‘Library’ in the left sidebar of Serato DJ, virtually every Track in the main window is a brown/bronze colour & is not found when loaded onto a virtual deck.  Returning to ‘Setup’>’Library + ‘Display’ tab in Serato, if I UNcheck ‘Show iTunes Library’ then return to Serato, in the main window most tracks are in white & play as normal.  The problem then is that the sidebar is empty & the tracks displayed in the main window of Serato DJ are listed completely at random – no Playlists, Default or my own ones, are listed.
So, the main question seems to be - why can’t Serato DJ find my music when it is moved from the default location, if iTunes can?  Is there a way to manually edit where Serato DJ looks for my music, as there is in iTunes (‘Edit’ tab>Preferences>’Advanced’ tab>’Change’ button (under ‘iTunes Media folder location’ box) ?
As I write this support request, another thought has come to me.  Can the ‘iTunes Media’ folder be in different places on different devices, e.g. 2 different laptops & a desktop PC ?  What about music stored in the ‘iCloud’ ?  On one laptop, in the Cloud field in iTunes, approx. 1600 tracks, of an approx total 2800, have no symbol; 1100 tracks are ‘greyed out’ but have a cloud symbol with a down-pointing arrow inside.  Hovering over this symbol it says ‘Download from iCloud’ but I have tried double-clicking & right-clicking on the track, neither of which give me a ‘Download’ option; 55 are again bold, with a cloud symbol & an ‘x’ inside it.  Hovering over this symbol it says ‘Removed from iCloud’ – I don’t recall removing/deleting any tracks from the iCloud!; Lastly, 2 tracks (Bold) have a cloud symbol with a ‘\’ symbol across it. These are labelled ‘ineligible’, but with no instructions on what to do about this.
In iTunes Help these symbols are explained but no instructions on how to correct these issues is given.
If you require any further information, please let me know.

Answer 1

It would seem mesa and virtualbox aren't playing nice atm (nothing to do with gnome) https://bbs.archlinux.org/viewtopic.php?id=194678. Hopefully someone somewhere is fixing this.