PermaProps Error in console - can't make props permanant

[BitPlanet]

Haio,

When I try to make props permanent on the server, The prop/npc/entity disappears and SOMETIMES it will post "Invalid entity" in chat. This is the error it shows when I try to make something permanent:

[IMG]http://i.imgur.com/to873CR.jpg[/IMG]

I have tried re-installing and using both a standalone version that I downloaded and getting it off the workshop. I either need a fix for permaprops OR a tool that does the same job :)

Thanks!
(PS, I really appreciate ANY form of help as this is the only thing stopping my server from going public)