Hi. I am getting an error using the slider joint as well. (The error flashes on and off too fast for me read it.) I have been trying to constrain it to the world as well.

This is listed as fixed below and this topic is from May (3 months ago). Is this fixed in any public version or does fixed refer to the private beta?

What is the best simple work around for this assuming this is still bugged in the public release? Is constraining it to another physics object the only method for a slider constraint to work? Does the 2nd physics object have to be active? What restrictions are there? It can't have a mass of 0?

thanks for any help,
Jason