No subject

--- snip ---
6.792: PFE2: Failed to connect to server; error=0x0
--- snip ---

This is most likely due to undocumentd sfc ordinal 3 returning 0, but harmless.
The installer looks at return value >0 and might actually do more sfc stuff if
connection to "server" succeeds (whatever this means).

--- snip ---
6.795: GetCatVersion:  Failed to retrieve version information from
C:\windows\system32\CatRoot\{F750E6C3-38EE-11D1-85E5-00C04FC295EE}\Tmp.0.KB915865.cat
with error 0x57
6.796: GetCatVersion:  Failed to retrieve version information from
C:\windows\Tmp.0.KB915865.cat with error 0x80092004
6.835: InstallSingleCatalogFile: MyInstallCatalog failed for
Tmp.0.KB915865.cat; error=0x000004c7.
6.836: DoInstallation:MyInstallCatalogFiles failed:STR_CATALOG_INSTALL_FAILED
6.836: CleanupTrustedInfFile: GetFileAttributes for
C:\windows\system32\CatRoot\{F750E6C3-38EE-11D1-85E5-00C04FC295EE}\oem0.cat
failed: 0x2
6.859: DeRegistering the Uninstall Program -> KB915865, 0
6.859: Failed to install catalog files.
9.117: Message displayed to the user: Failed to install catalog files.
9.117: User Input: OK
9.118: Update.exe extended error code = 0xf01e
9.118: Update.exe return code was masked to 0x643 for MSI custom action
compliance.
--- snip ---

So this is essentially the same as in first post from bug report.

The first failure is correct due to KB915865.cat already present in catroot, a
temp .cat is created in "C:\\windows\\Tmp.0.KB915865.cat" on not in
"C:\\windows\\system32\\CatRoot\\{F750E6C3-38EE-11D1-85E5-00C04FC295EE}\\Tmp.0.KB915865.cat"
where the first try goes.

The second try:

--- snip ---
0035:Call crypt32.CryptSIPRetrieveSubjectGuid(001e84f0
L"C:\\windows\\Tmp.0.KB915865.cat",00000000,001cad9c) ret=71a7de2c
0035:Call KERNEL32.CreateFileW(001e84f0
L"C:\\windows\\Tmp.0.KB915865.cat",80000000,00000001,00000000,00000003,00000080,00000000)
ret=606b3ae1
0035:Ret  KERNEL32.CreateFileW() retval=00000104 ret=606b3ae1 
...
0035:Ret  crypt32.CryptSIPRetrieveSubjectGuid() retval=00000001 ret=71a7de2c
0035:Ret  wintrust.CryptCATOpen() retval=001cad88 ret=010710c4
0035:Call wintrust.CryptCATGetCatAttrInfo(001cad88,01025430 L"SPAttr")
ret=010710f2
0035:fixme:wintrust:CryptCATGetCatAttrInfo 0x1cad88, L"SPAttr"
0035:Call KERNEL32.SetLastError(80092004) ret=71a7ca2e
0035:Ret  KERNEL32.SetLastError() retval=80092004 ret=71a7ca2e
0035:Ret  wintrust.CryptCATGetCatAttrInfo() retval=00000000 ret=010710f2 
...
0035:Call KERNEL32.MultiByteToWideChar(00000000,00000000,01025388
"GetCatVersion:  Failed to retrieve version information from %S with error
0x%lx",ffffffff,00000000,00000000) ret=6c516e1c 
...
0035:Call crypt32.CryptSIPRetrieveSubjectGuid(001e84f0
L"C:\\windows\\Tmp.0.KB915865.cat",00000000,001cad9c) ret=71a7de2c
0035:Call KERNEL32.CreateFileW(001e84f0
L"C:\\windows\\Tmp.0.KB915865.cat",80000000,00000001,00000000,00000003,00000080,00000000)
ret=606b3ae1
0035:Ret  KERNEL32.CreateFileW() retval=00000104 ret=606b3ae1
...
0035:Ret  crypt32.CryptSIPRetrieveSubjectGuid() retval=00000001 ret=71a7de2c
0035:Ret  wintrust.CryptCATOpen() retval=001cad88 ret=010711c7
0035:Call wintrust.CryptCATGetCatAttrInfo(001cad88,01025440 L"SPLevel")
ret=010711ef
0035:fixme:wintrust:CryptCATGetCatAttrInfo 0x1cad88, L"SPLevel"
0035:Call KERNEL32.SetLastError(80092004) ret=71a7ca2e
0035:Ret  KERNEL32.SetLastError() retval=80092004 ret=71a7ca2e
0035:Ret  wintrust.CryptCATGetCatAttrInfo() retval=00000000 ret=010711ef
...
0035:Call msvcrt._vsnprintf(0033a94b,000007f7,01026ef0
"InstallSingleCatalogFile: MyInstallCatalog failed for %s;
error=0x%08lx.",0033b17c) ret=0106b900 

--- snip ---

The installer tries to retrieve the catalog version by CryptCATGetCatAttrInfo(
.. "SPAttr") and then SP (=service pack version?) by CryptCATGetCatAttrInfo(
... "SPLevel") on both locations.
This missing functionality is most likely harmless but might be added one day
by crypt component maintainers ;-)

The real problem becomes only visible when on one debugs the installer itself
and looks again at trace logs.