Cannot read configuration file because it exceeds the maximum file size.
I'm getting above error because my rewritemap.config file size is more than 250KB (Windows 2008 R2 SP1 server with IIS 7.5
If you have access to registry and if you really need file greater than 250kb, you can change value in Registry Key.
For an x32 system:
Create the Key:
HKLM\Software\Microsoft\InetStp\Configuration\
Add the DWORD value:
MaxWebConfigFileSizeInKB
For an x64 system:
Create the Key:
HKLM\Software\Wow6432Node\Microsoft\InetStp\Configuration\
Add the DWORD Value:
MaxWebConfigFileSizeInKB
Be sure to reboot or restart the application pool. This answer to a related question may also inspire.
Note: If there are not the key, you can just create it. how to create a key on regedit
Other alternative is to split the .config files. http://forums.asp.net/t/1961321.aspx?Split+web+config+rewrite+rules+in+separate+file