Unfortunately I ran into the exact same problem as Littlewoods.
I successfully installed a fresh Windows 7 parallel to my old Windows Vista (which wasn't tolerable towards the end anymore, but I wanted to keep it for several purposes).
First I used Acronis OS Selector to switch between the two, but that program is really dangerous, which I found out the hard way. To make a long story short, I had to use the Windows 7 Installation disk several times to repair an unbootable system and in addition it rendered my external USB harddrive (for backup purposes) completely unreadable by killing all the partitioning information.
I got that issue solved by buying a great partition recovery utility, but decided to uninstall OS Selector for good (which of course rendered my system again unbootable, but I was already experienced in solving that issue by then :-) ). I can only warn people to use that tool. Googling will bring you plenty of hits with people having lost important data because of this badly written piece of software.
So I looked for alternatives and stumbled across OSL2000 Boot Manager. It got several recommendations on sites comparing boot managers and looked exactly like what I needed.
Taking up no space on the harddrive (it doesn't install itself into its own primary partition like many boot managers do, nor does it install itself onto an existing partition) by just using a little code in the MBR sounded great. I don't need any fancy graphics to select the OS I want to boot next, so I am good with the DOS like interface. It also allows the automatic hiding of other primary partitions, so I could maintain my completely independent two primary Windows Partitions as I did before. Perfect.
So after using it for a while, I wanted to register the software (to pay the developer for his work and to get rid of the little nag screen).
And then I ran into the exact same issue as Littlewoods. I started the setup.exe in C:\OSL2000, clicked on register, entered the code and got the message that registration was successful (only through a so called secondary server though, the primary had produced a connection time-out) and I had to reboot the computer to finish the registration process.
And so I did. Only to end up in front of a big read warning message saying:
Version mismatch (old or invalid boot module detected).
To register, please visit www.osloader.com, download a
fresh copy of OSL2000, install it first and then register.
If you need further help, please visit www.osloader.com and
click on the [Support] button. We are eager to help you.
So I started up Windows 7 again, downloaded a fresh copy of OSL2000 again (which was again version 9.27 Platinum), installed it, registered it again (again only the secondary server responded), got a success message and thought I would be good now, but ended up again in front of the same problem.
So I tried all kinds of other stuff. I un-installed the OSL2000 boot manager, deleted the directory, rebooted, overwrote the MBR with a standard MBR to make sure to rid of any remnants etc. etc.
In the end NOTHING WORKED.
So I send a message to the publisher. Once through his support form on the website (including my order id to get "priority support") and later again using the eMail address specified in the registration eMail I had received from Share-It!/MyCommerce (the registration service).
Apparently he hasn't changed his MO, because like Littlewoods I didn't get any response so far. (The developer also hasn't responded to a question I had sent to him several weeks ago).
The weird thing is, this support forum is the only hit I got at all when googling my problem. Seriously, if you enter
osl2000 old or invalid boot module detected
into the google, the only useful hit is this forum. If you put "old or invalid boot module detected" in quotation marks, you literally only get on hit.
So I am wondering now, how the BIOS has anything to do with the issue, since it looks like Littlewoods got his problem solved this way. It seems to make sense that the program writes something into the BIOS, because I completely rewrote the MBR and was puzzled how anything could be left in there.
Any help would be appreciated. Especially since the nag screen seems to take longer and longer to go away with every reboot of the computer.
I also want to let other people know who might be running into this problem, that "OSL Corp." didn't respond to a customer back in January 2012 (according to Littlewoods) and seems to stick to that kind of "service" in February 2013. Maybe you should look for an alternative boot loader, before throwing money at them.
I will try to erase my BIOS (great, what kind of hoops you have to jump through nowadays to solve problems that software causes that wasn't even cheap in the first place) and if that gets the "old boot module" erased, so be it. If not, I will ask the registration service for a full refund. Maybe that gets the guy to respond to my problem.