PassiveTeX uses quite a lot of TeX's resources.  You may find it
necessary to increase the size of some of TeX's resource pools by
editing the file %%TEXMFDIR%%/web2c/texmf.cnf with any text
editor.

If you change %%TEXMFDIR%%/web2c/texmf.cnf, delete the word
"original" on line 1 of the file.  This will prevent future
installations of TeX from overwriting changes you've made.