The architectural constraints have been removed in recent versions of Calc, but the design problems have not been addressed. In my (few) tests, Calc is nearly unusable with large files. Even a simple table with 100k rows is terribly slow, especially with loading and saving, and the temporary files required are huge: a hundred-fold larger than the input file.
I'd expect that a 30Mb file is simply not going to work: there just isn't enough time, memory and disk space.
AOO 4 • Linux • Fedora 17