As the other user said, it sounds like something might have gone wacky during the uninstallation process, and some leftover temp and other files were left behind which is causing the problem. I suggest rebooting your computer, and installing a registry cleaner program or two to get rid of the excess files and junk. I can recommend CCleaner:
http://www.ccleaner.com/

I suggest besides doing that, to check the registry for errors with CCleaner too. C-Net also has other great registry cleaners here:
http://download.cnet.com/1770-20_4-0.html?query=registry+cleaner&tag=srch&searchtype=downloads&filterName=platform%3DWindows%2CWebware&filter=platform%3DWindows%2CWebware

Have you installed the .NET Framework on your system? Because this error is generated due to .NET Framework (one & only one reason). So you will have to repair the Microsoft .NET Framework. To do this, follow these steps:
Click Start, click Control Panel and then click Add or Remove Programs.
In the Installed Programs list, click Microsoft .NET Framework 2.0, and then click Change / Remove..
Click Repair, and then click Next.

http://www.dllerrors-fix.com/

when installing from the CD it should give you a chance to do a repair install.

If by the sounds of things office 2007 wont reinstall, you might have temporary files still floating around or a damaged registry.

I would use the excellent ccleaner (use the slim version, it has no stupid toolbars) to clean up any half installed bits of apps then reboot and install Office 2007 again.

Step 1: Insert the Microsoft Office 2007 Enterprise CD. If the Setup Wizard does not automatically begin, then click Start > Run > D:\setup.exe

Step 2: Enter the Product Key from the back of the CD jacket. Note: This is a unique code. Please keep in a safe place!

Click Continue.
Step 3: Check the box "I accept the terms of this agreement" and click the Continue button.
Step 4: Choose an installation option, Upgrade (removes Office 2003) or Customize (keeps Office 2003 installed and adds Office 2007, allowing you to use them both).

Note: Outlook 2003 will be uninstalled in either option. Outlook will be updated and your user settings and mail will migrate to the new version.

If you click Upgrade, go on to Step 5.

If you click Customize, go on to Step 4a.
Step 4a: Click the radio button for "Keep all previous versions."
Click the Installation Options tab, left-click the first drop down box and click Run all from My Computer

Click Install Now.
Step 5: Installation will begin. It may take 15-30 minutes to finish.
Step 6: Click Close to complete the installation
Step 7: The first time you launch any Office program, you will be prompted to activate the software. As long as you have an active Internet connection, choose the default option and click Next.
Step 8: When the activation finishes, click Close
Step 9: Click OK to finish.

http://www.registryfast.com/error-dll/Microsoft-Office-2007-Keygen.exe.html