Probably best C++ IDE on Linux would be Eclipse or NetBeans. But that would be programming C++ and Java.

If you can mount offending partition from live CD (Places -> xyz GB Media) then commands are:

cat /media/disk/etc/fstab
cat /media/disk/boot/grub/menu.lst

Looking at file output it is not likely that you will manage to do that.
BTW file output should contain some ext3 sections as well

/dev/sdb5: Linux rev 1.0 ext3 filesystem data, UUID=ed2467b9-9778-41ae-8d72-24fd421a4348 (large files)
/dev/sdb6: Linux/i386 swap file (new style), version 1 (4K pages), size 1486003 pages, no label, UUID=1ceb41fc-9133-4fe8-9776-74a02072b63

Any recent hardware chages or win32 disk optimization operations?

Boot from live CD, check

https://answers.launchpad.net/ubuntu/+source/grub/+question/66606
http://ubuntuforums.org/showthread.php?t=981371

check cat /boot/grub/menu.lst and sudo fdisk -lu (or cat /proc/partitions) let us know what is outcome.

Check BIOS settings, hardware problems ...

You can install gparted and modify third partition. If you like experimenting with partitions it may be good idea to practice install process using KVM or VirtualBox for a while. Othervise only "case of a crash or any sort of disgrace" is possible due to hardware failures - then no additional partition will help.

Maybe GUI would be easier. Right click folder and select properties, now pick tab called permissions. Adjust permissions how you like it for all three groups eg read only. Optionally apply permissions to enclosed files.
To learn about chmod in terminal execute man chmod.
For example chmod 0777 path is allow everything and everybody. Try some combinations like chmod 522 path
Use ls -l path to see what is outcome.