I don't have my N900 in front of me right now to try this for you, but when I have this problem on my desktop, I try this as root in the xterm:

(view file max set in proc)
cat /proc/sys/fs/file-max
1048576

(view file max set in Pam.d, but I don't think maemo uses pam.d...)
cat /etc/security/limits.conf
* soft nofile 1048576
* hard nofile 1048576

(view file max in sysctl)
sudo cat /etc/sysctl.conf
fs.file-max=1048576

If you find that the N900 has any of the above files and you change them, reboot to make the change active. Then after reboot, run the following command to view the current file max:

ulimit -n
1048576