Try this
Here is how I have my system set up.
Vista & Seven share first drive.
Simply Mepis 8.0 on second drive
Simply Mepis 8.5 (two different installs) on third drive
Vista contains Easy.
Grub is installed on Root of all three installs of Mepis
Remove all Linux entries from Easy
Select one Linux entry to be "in charge" of all Linux entries, and create an entry for that ONE only. This one will eventually contain the GRUB entries for all Linux entries.
Point Easy to that entry. Should boot OK.
Boot into Linux
Navigate to each Linux install that you have & locate the "menu.lst" file and copy the appropriate boot line into the Bootable Linux "menu.lst" file. I find that there is a lot of useless crap in the "menu.lst" file. I only use the first entry.
What you should have then is TWO entries in Easy. One for Seven, and one for Linux. When you select the Linux entry, Grub should open the primary "menu.lst" showing all of your Linux installs. Select the one you want & away you should go.
The one thing that I am a bit nervous about is GRUB 2. I have never used it, Therefore, I haven't a clue if it will play well with GRUB.
I hope this gives you some assistance. I am a rookie at Linux, but learning. I really like Simply Mepis.
www.mepis.org
Best to you
Jerry in Anchorae