You have a memory leak. I've had this happen when querying from xl
files. There's also a kb article about it with text files, but I can't
find it right now.

This is similar - http://support.microsoft.com/kb/319998. The issue
seems common across apps and file types.

Basically, the data source has to be closed for memory to behave,
otherwise it just keeps allocating (or trying to) more memory. Hope
this helps.

Cliff Edwards