Lot of thanks for your advice.
I'm testing MyDLP on Windows 7 download "MyDLP Windows Endpoint - x86 Version:0.5" on; MyDLP Downloads - MyDLP Windows Endpoint Installer
Windows 7 (32bit) is running as VM on the virtual machine;
Host - Ubuntu 1010 desktop 64bit
Virtualizer - Oracle VirtualBox
VM (guest) - Windows 7 32bit
After extracting the zip file there are 4 software;
mydlp-endpoint-0.8.0 (Configuration settings)
mydlp-endpoint-0.8.0 (Windows Installer Package)
I have the first 3 software installed without complaint. On installing "Windowsinstaller-KB893803-v2-x86" it complains "Not enough storage is available to process this command". There are plenty of space on the VM at least 30G not used.
Then according to following thread; Windows Installer not working for .msi installations.
I have been trying for 2 days without a breakthrough. I couldn't discover any permission problem.
I also found similar threads having this problem; Not enough server storage | Windows Problem Solver Not enough storage is available to process this command. - Tech Support Forum Not enough storage is available to process this command - Microsoft Answers
I re-read the document on MyDLP website. According to "MyDLP Endpoint Installation Howto" MyDLP Endpoint Installation Howto - MyDLP - Data Leak Prevention - Easy, Simple, Open Source
Prerequisites softwares are;
1.Windows Installer 3.1
2..NET Framework 2.0 SP2
Therefore I started wondering whether they have been already installed on Windows 7.
That is the complete story.