Right the LrC catalog Can NOT be on a Networked drive. It has to be on a drive connected directly to the computer the LrC program is running on. That drive can be Internal or External.
Not sure why you don't understand that error you got.
In the future, So people don't have to download the image you have attached, please use the Insert Photos icon found in the Tool Bar of the Post and Reply text entry dialog window as pictured below. Since you Can't Edit your original post to remove the Attached screen shot Please include the screen shot you attached to a new reply to this conversation by clicking the Blue Reply button under your original post and use the Insert Photos icon in the tool bar. The Insert Photos icon is this one in the Tool Bar.