windows7 64位系统安装cad2012的时候总是安装不成功。急求高手作答！

刚刚安装到microsoft.net framework的时候就错误了。日志如下：
2012/3/26:23:09:39 sony SONY-VAIO PageOpen InstallCompleteDialog
2012/3/26:23:10:09 sony SONY-VAIO === Setup ended ===

2012/3/26:23:11:28 sony SONY-VAIO === Setup started on SONY-VAIO by sony ===
2012/3/26:23:11:28 sony SONY-VAIO Launch
2012/3/26:23:11:35 sony SONY-VAIO === Setup ended ===

2012/3/26:23:11:28 sony SONY-VAIO === Setup started on SONY-VAIO by sony ===
2012/3/26:23:11:28 sony SONY-VAIO Launch
2012/3/26:23:11:35 sony SONY-VAIO PageOpen LaunchDialog
2012/3/26:23:11:43 sony SONY-VAIO PageOpen LicenseDialog
2012/3/26:23:11:46 sony SONY-VAIO PageOpen ProductInfoDialog
2012/3/26:23:11:49 sony SONY-VAIO PageOpen ProductSelectionDialog2
2012/3/26:23:11:50 sony SONY-VAIO PageOpen FullProgressDialog
2012/3/26:23:11:50 sony SONY-VAIO Installing .NET Framework Runtime 4.0 Language Pack: E:\TDDOWNLOAD\AutoCAD_2012_Simplified_Chinese_Win_64bit_Trial\3rdParty\NET\4\wcu\dotNetFramework\dotNetFx40LP_Full_x86_x64_2052.exe /q
2012/3/26:23:11:57 sony SONY-VAIO Install .NET Framework Runtime 4.0 Language Pack Failed Installation aborted, Result=1603
而且我看我电脑里装的是microsoft.net framework4.0的。

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