Script Error - Error executing the advanced shipping plug-in script.

[stupidlammer]

Error stated below, appreciate if anyone could assist.
Error occurs when one clicks next from checkout page 0.

A General Script Error Occurred

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Error: Error executing the advanced shipping plug-in script. Global symbol "$DefaultWeight" requires explicit package name at (eval 41) line 510. Global symbol "$DefaultWeight" requires explicit package name at (eval 41) line 791. Global symbol "$sOptimalWeight" requires explicit package name at (eval 41) line 794. Global symbol "$sOptimalWeight" requires explicit package name at (eval 41) line 795. Global symbol "$sOptimalWeight" requires explicit package name at (eval 41) line 818. Global symbol "$sOptimalWeight" requires explicit package name at (eval 41) line 819. Global symbol "$sOptimalWeight" requires explicit package name at (eval 41) line 821. Global symbol "$sOptimalWeight" requires explicit package name at (eval 41) line 988. Global symbol "$sOptimalWeight" requires explicit package name at (eval 41) line 989. Global symbol "$sOptimalWeight" requires explicit package name at (eval 41) line 992.
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Press the Browser back button and try again or contact the site owner

[leehack]

Website purge and refresh required.
You could also search the forum on '$DefaultWeight' to see some other people who've had the same problem.

[jont]

Have you made any modifications to the cart area? However apparently minor ... it is very very easy to kill the cart with innocuous alterations.

[stupidlammer]

Website purge and refresh required.
You could also search the forum on '$DefaultWeight' to see some other people who've had the same problem.

Thanks, ill check it out first.