infoRouter keeps warehouse path definitions in a file called "warehousepaths.xml" which places in "[infoRouter application path]\config" directory.
This exception has occurs when the "Network Services" account or "Impersonated User account" do not have the read permission to the config path or specifically to this file.
This exception has occurs when this file is missing or corrupted..
Generally this happens right after a server migration. Please make sure you copied all the files while migrating infoRouter application.
Make sure "Network Services" account or "Impersonated User account" has "full control" permission on the config path and all files underneath.