1) Make sure you are installing 32 BIT ODT 184.108.40.206.20 or later (currently "ODTwithODAC1120320_32bit.zip") Note: Not the 64 bit install!
2) Make sure you are not using Visual Studio Express Edition (not supported)
If so, if you are still having problems you can email me the install logs to christian (dot) shay (at) oracle (dot) com
The log is located in:
C:\Program Files (x86)\Oracle\Inventory\logs
Make sure the time stamp is for your most recent install attempt.