I'll duplicate the solution post here:
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WOOOOHOOOO!!! Hallelujah!!! It's fixed. It appears to be related to Snapsis PageBlaster. We compared the config file settings for pageblaster between 2 hosts both running 5.4.2
One was throwing the javascript errors and one was not. We modified the one that wasn't working to reflect the settings of the one that was and eureka! For those that may be interested here are the settings for our snapsis file that were changed:
Set the trace level to none like so:
<trace level="None" file-path="/PageBlaster.trace.webinfo" />
Include these exclude paths:
<path pattern="(/admin/|/host/)" excludeFrom="All" />
<path pattern="ctl[/=](edit|module|tab)" excludeFrom="Replacements" />
<path pattern="(/admin/|/host/|cart|404|fck)" excludeFrom="All" />
<path pattern="\.js$|\.css$|\.html$" excludeFrom="Replacements" />
<path pattern="jquery" excludeFrom="JSMin" />
I don't know if you'll need all of those exclude paths but that's what worked for us. Hope this helps someone