Request Limitation?

[headalien]

Hi--thank you for the very useful plugin!

Quick question: We are trying to insert new subscribers from another source.
To accomplish this I pull a list of new email addresses (from other system) then use a foreach loop to check whether each address is in the database (subscriberFindByEmail()) . If I limit the query to under about 50 addresses, the results returned are accurate (empty for not in system, ID if they are). Once we do more than 50 or so, even the addresses that are already in the system return an empty result. It this simply a limitation of the system, or is there something I can add or adjust allow larger loops (up to about 200 addresses). Thank you for your help