It means the symbol can't be found.
When I try it on my computer, I get these kind of problems with thread safety turned on but not when that is turned off.
Unfortunately I don't know how to solve it.
The library was written with in Objective C with XCode but I can't find much information on how to create an OS X user library when it comes to outputting PB compatible strings.
I've moved everything in my program into a main thread because i had problems with mac os and threading. I have had big speed issues and now I turned threadsafe OFF and the speed of my program is just amazing. Now its obvious that Purebasic is pure speed!