Bypassing windows update error 0x80096002

I am getting this error when I try to install some .msu files (WMF 3 if it matters).

Now, the error is saying that the certificate is invalid. However, I looked at the certificate (if anyone is curious, here is the public key for the cert:

30 82 01 0a 02 82 01 01 00 ee 5b be 7d 11 24 e3 86 06 e0 66 ff 48 b5 17 bd 02 e4 b4 0c 32 f0 72 3e 7d 2e 87 d7 4e a1 b1 a7 43 2f f7 65 9e 31 e1 32 31 45 ae d7 c1 24 84 21 d7 2e b5 84 7e fa 35 d3 53 1c d7 b6 51 1e 4f ce 66 b9 eb b7 0c 02 fd 29 5c ad a8 87 f6 ca 22 b4 d5 bf 08 75 f5 8a 70 8f 63 d7 ef 8a 1e e9 8f 43 24 64 5a d3 87 7d 90 6d 3b ac 76 cd 57 36 7d e8 bc 10 56 ac 98 f0 89 5d 2e 64 c6 af 26 09 5e 1e 63 15 f1 3d bf 16 8f 99 88 02 c3 30 b7 c1 0b 60 1f 0f 72 cc d6 b7 a8 35 12 86 9b a1 0b 0a e6 93 5b 8e fa 54 9c c1 f3 19 5f 42 8d 12 9f 1d 3f 90 b7 27 13 83 19 32 82 1d f3 d9 87 d4 21 b2 3c a2 b6 07 4f d7 24 aa ee 8d f5 b3 d9 fa f9 39 4f a7 e9 f2 af 59 52 f4 dc 41 9b 2f 11 70 63 dd ea de aa f1 6d 21 04 10 53 33 bb b2 4f c5 e1 53 b2 41 65 47 6e 37 f6 bc e9 9b 16 41 91 6b 2e 5b 30 c3 02 03 01 00 01

)

Now, I have already tried installing the certificate, and it said it went though, but it still gives me this error.

So what I am looking for is a way to:

1. Figure out what is causing this error, and actually fix it
2. Find some way of installing the .msu without it checking for a signature.

As an aside, the rest of the time, my windows update appears to work fine.

Edit: I attempted to install the update manually (based on this KB article) but I got stuck at the pkgmgr line. It runs without errors, but also without doing anything.

Edit 2: Thanks to Oliver Salzburg, I have the following additional information:

2012-08-15 09:55:46:203 4532 17e0 Misc =========== Logging initialized (build: 7.8.8400.0, tz: -0400) ===========

2012-08-15 09:55:46:203 4532 17e0 Misc = Process: C:\Windows\system32\wusa.exe

2012-08-15 09:55:46:204 4532 17e0 Misc = Module: C:\Windows\System32\wuapi.dll

2012-08-15 09:55:46:203 4532 17e0 COMAPI ----------- COMAPI: IUpdateServiceManager::AddScanPackageService -----------

2012-08-15 09:55:46:204 4532 17e0 COMAPI - ServiceName = Windows Update Standalone Installer

2012-08-15 09:55:46:204 4532 17e0 COMAPI - ScanFileLocation = C:\6c5d513b31af3c42f33ba22b57\wsusscan.cab

2012-08-15 09:55:46:214 4532 17e0 COMAPI WARNING: ISusInternal::OpenOfflineSyncSource failed, hr=80096002

2012-08-15 09:55:46:214 4532 17e0 COMAPI - Exit code = 0x80096002

The problem simply put is that windows 8 already comes with powershell V3. Trying to install int again causes problems as the files are already there, and similar issues.