There may be a 2 gigabyte limit on the size of a single
file, imposed by your operating system (not by AFNI).

The adwarp program will not only apply the orig->acpc
transformation to the EPI data, it will also resample
that data to match the grid of your hi-res anatomy.
But that can increase the file size by a factor of 100
or more, which in turn can make it easy to clear a 2 Gig
file size limit.

If you want to restrict the grid spacing of the result,
you can apply the '-dxyz ddd' option to the adwarp
command.

Depending in what you are doing, it may make sense to
analyze the EPI data in orig space _before_ transforming
it for some sort of group computation. That way you
would be transforming a dataset having a smaller number
of sub-bricks (only the number created by your statistical
computation, not the overall length of your time series).
It also allows the statistics to be computed from the raw
data, as opposed to data which has been smoothed by some
transformation.

- rick