It would seem that the same problem with 5.12 is also effecting your 4.86 installation - that posted variables are not being passed to the script. If you had 4.86 running before and are running 4.86 now, the question I would ask your ISP is did anything change more recently that would possible have changed the conditions on your server? I ask this because if it worked before and you are back onto that software, it should work the same as before, right?
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