Installing ArcGISDesktop931.msp from the 9.3.1 updates media kit leaves behind an extracted file in the Windows temp directory, whereas other .msp files are cleaned up. A Windows installer file with the same size of ArcGISDesktop931.msp remains. The size of ArcGISDesktop931.msp is 552,029KB. This could potentially use up the available space on the hard drive or leave limited space for the user.
This is a known software defect (NIM045529).
Upgrade the version of Windows Installer to 4.5 or later; the later version of Windows Installer cleans up the temp directories after the install.