This is the library that will allow your phone to read Linux ext2 partitions. It is very important if you use partitioned flash card (see the Partitioning your SD card tutorial). The installation is very simple - download the ext2.o file, upload it to the phone and type the following command in telnet:
# insmod /<path>/ext2.o
where <path> is the path to your file (the place where it is uploaded).
Download Ext2.o HERE