Yes, I looked at the log, but too much mumble-jumble for me ( I was a programmer 35 years ago, not anymore ... *grin*). It 'looked like' it returned error messages after some DX entries, but as far as I can tell my DX11 installation is normal and I don't see any entries in the registry telling me wrong....
I had the exact SAME error message on installing 3 times.... but ONCE it let me 'ignore' them and P3D installed anyway and it ran..... minus my X53 rudder pedals.
After the second install and the THIRD installation I got the same error message again at the end of the process, but it then also failed to install altogether.
I posted part of the log file on P3D forums....... but no (serious) reply.....
[19AC:14CC][2013-11-27T12:28:39]i304: Verified existing payload: cab47CD946571C844D202F86FF7BACD3339 at path: C:\ProgramData\Package Cache\{5DD3CF5D-9573-44A8-9543-D65BED953192}v2.0.9448.0\data9.cab.
[19AC:1604][2013-11-27T12:28:39]i301: Applying execute package: VCREDIST100, action: Install, path: C:\ProgramData\Package Cache\28C54491BE70C38C97849C3D8CFBFDD0D3C515CB\vcredist_x86_2010_10.0.40219.325.exe, arguments: '"C:\ProgramData\Package Cache\28C54491BE70C38C97849C3D8CFBFDD0D3C515CB\vcredist_x86_2010_10.0.40219.325.exe" /q'
[187C:0BA0][2013-11-27T12:29:11]i319: Applied execute package: VCREDIST100, result: 0x0, restart: None
[19AC:1604][2013-11-27T12:29:11]i301: Applying execute package: DirectX, action: Install, path: C:\ProgramData\Package Cache\9FD00F3BB8A870112DAE464F555FCD5E7F9200C0\redist\DXSETUP.exe, arguments: '"C:\ProgramData\Package Cache\9FD00F3BB8A870112DAE464F555FCD5E7F9200C0\redist\DXSETUP.exe" /silent'
[19AC:1604][2013-11-27T12:32:13]e000: Error 0xfffffff7: Process returned error: 0xfffffff7
[19AC:1604][2013-11-27T12:32:13]e000: Error 0xfffffff7: Failed to execute EXE package.
[187C:0BA0][2013-11-27T12:32:13]e000: Error 0xfffffff7: Failed to configure per-machine EXE package.
[187C:0BA0][2013-11-27T12:32:13]i319: Applied execute package: DirectX, result: 0xfffffff7, restart: None
[187C:0BA0][2013-11-27T12:32:13]e000: Error 0xfffffff7: Failed to execute EXE package.
[19AC:1604][2013-11-27T12:32:13]i330: Removed bundle dependency provider: {a48a43a7-4082-4dcc-9d34-f213a27a0452}
[19AC:1604][2013-11-27T12:32:13]i352: Removing cached bundle: {a48a43a7-4082-4dcc-9d34-f213a27a0452}, from path: C:\ProgramData\Package Cache\{a48a43a7-4082-4dcc-9d34-f213a27a0452}\
[187C:0BA0][2013-11-27T12:32:14]i399: Apply complete, result: 0xfffffff7, restart: None, ba requested restart: No