I am back to getting this error

Sorry - I've only just now remembered that the DynaLoader that shipped with 5.10.0 was broken as regards the mechanism that loads PGPLOT.xs.dll.
If you can upgrade to 5.10.1, or just grab a 5.10.1 DynaLoader.pm and stick it in there, then all should be fine.

Or, if you /msg me your email address I could send you the DynaLoader.pm that I use with 5.10.0.

Cheers,
Rob