Server Help Errors

[Bill]

So just recently i get this error spamming my console.

[Warning] Error loading Railcraft Save Data: Not in GZIP format

How do i go about fixing this? Only started once my power surged in my house.

[robert7]

go to the railcraft file in your world folder. right click and go to properties. on the general tab it will say 'opens with' change it to 7zip or winrar or whatever archiver thing you have