Downloaded mingw-get-inst-20100909.exe 2010.09.25 and ran it. Selected additional packages, requested refresh of package lists. Installer ran fine for a while, completed download of updated package lists, then died with error
Unable to execute file D:\MinGW\bin\mingw-get.exe
CreateProcess failed; code 32
The process cannot access the file because it is being used by another process.
The CLI installer clearly works --- I was able to use mingw-get to complete the installation from the command line, and went on to successfully build Coin-OR software, so the install seems to be correct. Looks like just a bug in the installer.
Seems repeatable. I tried a second, independent install while trying to sort out a Coin-OR bug report, saw the exact same behaviour.
System is Windows 7 64-bit running on Intel Core i7. All Windows patches installed, to my knowledge.