Error message when turning on the module

I get this error when I turn on the field encrypt module.

Warning: Invalid argument supplied for foreach() in FieldInfo->getFields() (line 187 of /modules/field/field.info.class.inc).
Warning: Invalid argument supplied for foreach() in field_info_fields() (line 496 of /modules/field/field.info.inc).

In dblog I get this error message:

Warning: Invalid argument supplied for foreach() in _field_encrypt_field_storage_pre_load() (line 253 of field_encrypt/field_encrypt.inc).

No fields get displayed until I clear the cache.

Everything seems fine after that. Just thought I'd report back.