[GRASS5] i.fft G_malloc: out of memory

[Gualter Barbas Baptista]

I'm trying to do a Fast Fourier Transform (i.fft) to a landsat image and 
I always get a G_malloc: out of memory. I thought that this was because 
all the system memory was exhausted, but then I checked that I still had 
about 100 mb free swap memory.
Is this something I'm doing wrong or is it some bug from this function? 
In Idrisi I have to pad the image to have lines and columns in a power 
of 2. Do I still have to do this in GRASS? If yes, how can I do a zero pad?

Thanks

Gualter