解决方法:
用记事本创建一个包含如下内容的 deffactory.dat 文件分别替换掉 setup\deffactory.dat、msdn\setup\deffactory.dat 即可。
[Version]
Signature = "$Windows NT$"
Provider="Microsoft Visual Studio 2008 Professional Edition - ENU"
Version=900.100.00
NullString=Null String
Lang=1033
[Scenario List]
vsscenario.dll
[Scenario Factory Information]
Default Scenario=11E4C8F3-425E-43b9-B689-8BFDF03342E2
Signature = "$Windows NT$"
Provider="Microsoft Visual Studio 2008 Professional Edition - ENU"
Version=900.100.00
NullString=Null String
Lang=1033
[Scenario List]
vsscenario.dll
[Scenario Factory Information]
Default Scenario=11E4C8F3-425E-43b9-B689-8BFDF03342E2