Error on installing under Windows Vista leads to inability to uninstall 5.2.3

Hello. Please pardon the cross-post - I posted this on the php.install newsgroup a couple of days ago, but there has been no activity on that news group, and I see that other installation issues are posted here. I have tried to install the following on my Windows Vista Home Premium System:

    php-5.2.3-win32-installer.msi

It has the following md5 sum, taken locally on my system:

    4d042f649d9c264477e1b421c64c6435

Installation seemed to go as expected. However, near the end of the installation process, I received a dialog window titled "PHP 5.2.3 Setup" with only an "OK" button and the following message:

    "The installer has encountered an unexpected error
    installing this package.  This may indicate a problem with
    this package.  The error code is 2738."

I pressed "OK", my only option, and then got to the page on the setup wizard with the "Finish" button. I hit the "Finish" button, was met with a dialog window with just an OK button with the message:

    "Fatal error during installation".

It seems that PHP was put on my system, and the path was set up correctly. Some simple tests indicate it is working, however, since I am a careful sort, I thought I would try to uninstall and start over. The trouble is that I can't. I can use the "Repair" option from ControlPanel->ProgramsAndFeatures->PHP, and it seems to "repair" without comment, but if I try to uninstall the software, or "Change" it in any way, I get the same two dialog boxes shown above, and the software does NOT uninstall. This makes me uneasy. I would appreciate help with any of the following (roughly in my priority order):

    1.  How can I uninstall this and remove it from my system?

    2.  What is error code 2738 and what does it mean?

    3.  What steps might I take subsequently to install without
        incurring this error?

Thanks in advance for any assistance.

    -Stephan G