Have you tried running the 1.2.6 stable version? That could very well
solve your problems... Presumably you also tried lowering your
sampling frequency?

If it is a resource handling issue with the linux beta, common fixes
can include lowering sample rate to </= 48000Hz, changing to a bit
depth of 16, record as mono, turning off autoscroll and meter, and
making sure your swap is mounted (check with "swapon -s") and large
enough.