Pre-req checker :
I) The pre-req checker fails while reading sql permissions
In my case SQL is remote .
SQL Server Sysadmin rights is the error messages.
Solution that worked for me :
1) add spn for sql using setspn command
2) add sccm server as local admin on sql server.
II) SCCM installation doesnot detect BITS and WebDav features. '
Following error appears in pre-req checker even if the features are installed.
BITS installed - error
BITS Enabled - error
Webdav Installed - Error
Webdav Enabled - Error.
This will occur if you are using windows 2008 R2 .
Install IIS 6 WMI compatibility component for IIS7 and re-run prereq checker.