"The path for the index location is not valid"
I recently faced this issue with the Sharepoint on the Central administration page that gives "The path for the index location is not valid" error message on the Manage search settings page on Application management
The problem occurs when you have changed the default location of the index file path
+ Either you can try bringing the index location back to where it was
+ Try stopping and starting the Osearch service give it the new location, and start it again, to do this make command line your friend.
+ To stop and start WSS search with command line use http://technet.microsoft.com/en-us/library/cc288507.aspx
+ To stop and start Office search with command line use http://technet.microsoft.com/en-us/library/cc262920.aspx
+ Try giving WPG group as full permissions on the index file location folder
+ Also give permissions to the C:\windows\tasks folder
+ As its a system folder and it will not give you permissions to edit the attributes on the command prompt run attrib -s C:\windows\tasks the go to security tab and add permissions and then again on command prompt run attrib +s C:\windows\tasks, to get the system folder attributes in place
Assume that the new index location you have provided is Drive D,
so go to the D drive and add the network service and the Worker Process Group (WPG) group as the following permissions listed
Traverse Folder / Execute File, List Folder / Read Data, Read Attributes, Read Extended Attributes, and Read Permissions
And I bet it going to work, if you are wondering why, this is because O search is controlled by a service named Office server web services and this service runs with the service account as Network service.
you can determine this from the IIS