To install Matlab 2007 on windows 7
1-Change Windows 7 Theme to the classic one (windows classic)
2-now the Matlab install will work correctly

To use Matlab with other windows 7 themes you have to change java used by matlab.
1- download latest java version and install it.
2- go to  C:\Program Files\MATLAB\R2007a\sys\java\jre\win32 you will find a file named jer1.5.0_07 rename it to Original_jer1.5.0_07
3- go to C:\Program Files\Java you will find file named jet6 (jetX for Xversion) copie it to C:\Program Files\MATLAB\R2007a\sys\java\jre\win32 
and rename it to jer1.5.0_07

Now you can use matlab with all themes.