Ardour crash after duplicating 194kB sample file

Hello everyone!
I need some help. Maybe your expirience tell me what to do.
I run 64Studio 2.1 Ardour 2.3 (rev.3029) AMD64 compilation.
I have a few sessions in Ardour, each has about 15 mono tracks and 7min long.
Not much plugins, just about five (MultibandEQ, SC4m, Gverb) in the hole session, and normalize on some tracks.

And here is the problem.

For exapmle:
Folder with one session has 720MB.
I load session and trying to add one bass drum kick sample file 194kB size and duplikate it.
After a few steps of duplicating I save with ctrl+s and duplicating again,
and after another few duplicates of file and the last ctrl+s, Ardour crash - system load very high, I think about 100%, I can see only graph on panel in IceWM.
All session crash and I’m back on desktop, jackd is still working.
I have to start session again.

I can only gues ther is problem with memory.

My system cofig is:

cpu - Athlon64 3200+ (2.2 GHz)
mo-bo - ASUS K8N
ram - 1 GB
hd1 - 40GB IDE Maxtor - for root - 6 GB on Ext3 fs
hd2 - 250GB WDCaviar SATAII - for sessions 60 GB partition on ReiserFS
audio - M-Audio Audiophile 24/96

Here is link to file to see some data about memoru usage:

As you can see after loading session there is only about 400-500 MB rem free and going down.

In this example swap usage is low but in other cases when swap was 512MB, it was full so I expand to 2GB.
It dosn’t help and all is same as described before.

Also I have done test session with only two tracks, one for kick track and second for lillte sample file for duplicating.
Again, nothing has changed.

Is there something I can do to work without this crashes?
I can add second 1GB ram module but can it help and for how long?
Why swap usage is so low?

Do you need some more data?

Best regards

Sorry for my bad english.