[Plugin: Pie Register] pie register not working in mulitiste-environment?

hi,

i habe a multisite setup with 2 blogs at domain.com and domain.com/en.

i installed the pie plugin, configured it, but when registering the usual register form is displayed, no sign of the pie plugin.

is it not working together with wp multisites?

greets

http://wordpress.org/extend/plugins/pie-register/