Drive space issues with Pofiles folder

Hello Gurus,

We have Clustered ( 2 Servers) BI 4.0 Sp05 instances on Win 2008. We are facing an issue with disk space . The POIFILES folder under BOBJ Install dircetory ( SAP BusinessObjects Enterprise XI 4.0\java\pjs\container\temp\poifiles) itself has 50 GB TMP files. This happens to be only on server 1.

Can some please throw some light on what exactly this POIFILES folder is?

Thanks

Karthik