disk space increase

Hi
I have QNX installed on my W2K system. It uses a single file as
filesystem.
I read root.qfs should increase size when needed, but when I tried to
untar Gimp then GTK, I was rewarded with a “no space left on device”.
There is plenty of space on the partition, though: boot.qfs could get
much wider. But it seems to stick to the size I specified at
installation time.

Is there an issue?
Thank you
– Denis.