You can also try this:
1. Navigate to the InfoPath Help menu and select Detect and Repair for InfoPath 2003 or Office Diagnostics for InfoPath 2007 to repair your InfoPath installation.
2. Download and install the Primary Interop Assemblies (PIA) for your version of Office:
Office 2003: http://www.microsoft.com/downloads/details.aspx?familyid=3c9a983a-ac14-4125-
8ba0-d36d67e0f4ad&displaylang=en
Office 2007: http://www.microsoft.com/downloads/details.aspx?FamilyID=59daebaa-bed4-4282-
a28c-b864d8bfa513&DisplayLang=en
3. Run the InfoPath / Office setup again.
But installing the PIA does not always work, especially in Office 2007. The following steps work in many stubborn cases:
1. Navigate to Control Panel:
2. Select Add or Remove Programs:
3. Select Microsoft Office 2007 and click on the Change button
4. Select the Add or Remove Features radio button and click the Continue button:
5. Click on the Microsoft Office InfoPath group
6. Click in the box to the left of Microsoft Office InfoPath. Clicking in this area will bring up a popup menu with options.
7. Select the Run all from My Computer option and click on Continue.
8. Follow the remaining instructions to install all components of InfoPath 2007 on your computer.