Unify! for Expression Blend

Hi everyone,
I am very glad to see such a add-in coming up but unfortunatelly I got the following error during install:
'Unify for Microsoft Expression Blend requires Blend 2 with SP1 to be installed.'
But that's exactly the version I have installed on my computer as the info box says:
Expression Blend 2 Service Pack 1, Version 2.1.1760.0 (German)

Anyone got the same problem or a suggestion what to do?

Thanks in advance, Rose M.

@Michael_Rose : Can you run the following from the command line from where the unify.msi is.

msiexec /i unify.msi /lvx unify.log and send the results to me please?

Thanks for your reply, I hope the relevant output of the command is contained in the following snippet, I can't post more in one comment, please let me know if you need further information.

Action start 22:03:37: INSTALL.
MSI (c) (00:BC) [22:03:37:078]: UI Sequence table 'InstallUISequence' is present and populated.
MSI (c) (00:BC) [22:03:37:078]: Running UISequence
MSI (c) (00:BC) [22:03:37:078]: PROPERTY CHANGE: Adding EXECUTEACTION property. Its value is 'INSTALL'.
MSI (c) (00:BC) [22:03:37:078]: Doing action: AppSearch
MSI (c) (00:BC) [22:03:37:078]: Note: 1: 2205 2:  3: ActionText 
Action start 22:03:37: AppSearch.
MSI (c) (00:BC) [22:03:37:093]: PROPERTY CHANGE: Adding BLENDEXELOCATION property. Its value is '"c:\Programme\Microsoft Expression\Blend 2\Blend.exe"'.
MSI (c) (00:BC) [22:03:37:093]: Note: 1: 1402 2: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall\{3891e1c9-8e9e-43e2-b009-6d008bcd7669} 3: 2 
MSI (c) (00:BC) [22:03:37:093]: Note: 1: 1322 2:  
MSI (c) (00:BC) [22:03:37:093]: Note: 1: 1322 2:  
Action ended 22:03:37: AppSearch. Return value 1.
MSI (c) (00:BC) [22:03:37:250]: Doing action: LaunchConditions
MSI (c) (00:BC) [22:03:37:250]: Note: 1: 2205 2:  3: ActionText 
Action start 22:03:37: LaunchConditions.
MSI (c) (00:E4) [22:03:37:250]: Font created.  Charset: Req=0, Ret=0, Font: Req=MS Shell Dlg, Ret=MS Shell Dlg

MSI (c) (00:BC) [22:03:38:234]: Note: 1: 2205 2:  3: Error 
MSI (c) (00:BC) [22:03:38:234]: Note: 1: 2228 2:  3: Error 4: SELECT `Message` FROM `Error` WHERE `Error` = 1709 
MSI (c) (00:BC) [22:03:38:296]: Product: Unify for Microsoft Expression Blend -- Unify for Microsoft Expression Blend requires Blend 2 with SP1 to be installed

Action ended 22:03:38: LaunchConditions. Return value 3.
Action ended 22:03:38: INSTALL. Return value 3.

Can you send the entire log to simon dot middlemiss at microsoft dot com

Following this up offline.

Same issues here.... also did the log thing, and the result is almost exactly the same as above. I am running Blend 4: 4.0.20901.0 to be exact.