>I'm trying to rebuild my EXE from a project that was previously in VFP7SP1
>
>VFP 9 gives me the error message "PJT file is missing or invalid"
>
>I have'nt changed a thing in that project.
>
>What should I do?

If you can open that project in VFP7 I thing you have SET TABLEVALIDATE problem :-)
Try in command window (make a GOOD backup first):

lnOldVal = SET([TABLEVALIDATE])
SET TABLEVALIDATE TO 0
USE YourProject.PJX EXCLUSIVE
PACK
PACK MEMO
REINDEX
SET TABLEVALIDATE TO lnOldVal

I am not sure if this will change anything :-)