This is exactly what to do as I had the same problem !
You need a clean install of it :) Follow al of this below :)
"The installer has detected that a previous version of Dimension Pro is currently installed. Please download the 1.5 update from www.cakewalk.com.
After receiving this message, your web browser may open and bring you to the Dimension Pro/LE 1.5 update on our website available here
If you experience this and you have already installed this update, then you are already up to date with the most recent version of Dimension Pro and you do not need to install this update.
If you have not installed this update, than you can get update to the latest version, Dimension Pro 1.5, by downloading the update from the update article.
If you wish to re-install Dimension Pro from the copy included with SONAR X1 Producer, then you will need to perform a clean installation of Dimension Pro. To completely remove traces of Dimension Pro, do the following:
1) Run the Dimension Pro uninstaller. This is normally done by going to Start
> Control Panel
and clicking on Programs and Features
(Windows Vista and Windows 7) or Add or Remove Programs
(Windows XP). In Add or Remove Programs, select Dimension Pro and click on "Uninstall".
2) After running the uninstaller, you will want to remove Dimension Pro's registry keys by doing the following.
a) Open the run prompt by holding down the Windows key on your keyboard and pressing "R"
b) In the Run Prompt, type in the following: regedit
c) Click [OK] and the Registry Editor will be opened
d) ***Back up your Registry before making any changes. You can do this by left clicking on "Computer" in the registry and then going to File
e) After backing up your Registry, you will want to delete the following registry keys. Delete the last folder in the chain of these keys by right-clicking on them and selecting "delete". In most cases, the folder you will be deleting will be named "Dimension Pro" or "dp". If you do not have some of the registry keys below, it is okay simply proceed to the next one on the list. Here are the keys to look for: HKEY_CURRENT_USER\Software\Cakewalk Music Software\Dimension Pro HKEY_CURRENT_USER\Software\Cakewalk Music Software\dp HKEY_LOCAL_MACHINE\Software\Cakewalk Music Software\Dimension Pro HKEY_LOCAL_MACHINE\Software\Cakewalk Music Software\dp HKEY_LOCAL_MACHINE\Software\Wow6432Node\Cakewalk Music Software\Dimension Pro HKEY_LOCAL_MACHINE\Software\Wow6432Node\Cakewalk Music Software\dp 3)
After deleting the above keys, manually delete the contents of your Dimension Pro folder. This will remove all of your multisamples. The default location for this is C:\Program Files\Cakewalk\Dimension
Pro or C:\Program Files (x86)\Cakewalk\Dimension Pro
4) Disable AntiMalware applications that may interfere with your software installations.
a) Open the Run Prompt again by holding down the Windows key on your keyboard and pressing "R".
b) Type in the following: msconfig
c) Click [OK] and the System Configuration utility will open.
d) Click on the Startup Tab and remove any check marks next to any AntiVirus or AntiSpyware applications that you may have installed on your computer.
e) Click [Apply] and then restart your computer. You can always recheck those items at a later time be revisiting the System Configuration utility.
5) At this point, it is safe to reinstall Dimension Pro from the installer included with SONAR X1 Producer using your CWDM-1.50-XXXXXX-XXXXXX
This wil get it all up and runing I had to do the samething
Was a bit of a pain in the ass but was worth the time