Autodesk Inventor Publisher

[#1]

I am getting this message when trying to open my project after I worked on it and saved it. Please help.

[#2]

It happens very often when I do an updated of my Inventor model.

Unfortunately, you must open the latest valid version for your file saved in the directory Oldversions.

To do this you must first install SP2.

[#3]

it doesnt seem like there is a directory OldVersions for Inventor Publisher (.ipb files), only Professional. changing the version of the assembly I have, wont be updated or even recognized in publisher because I cant even open the file in publiser

[#4]

I might be misunderstanding what youre saying though, can you explain it more and what to do. I have sp2 installed