I'm not sure how to do it with xACT (1.59).
I dragged a bunch of folders into the checksum window and got this applescript error:
md5sum: Allman Brothers Band - 2007-04-14 Wanee Festival [FLAC] {sbd}: Is a directory
md5sum: Allman Brothers Band - American University 12-13-70: Is a directory
md5sum: Aretha Franklin - Live at Fillmore West {2 CD} (2006) [FLAC]: Is a directory
md5sum: Bob Marley - Exodus (1977) [FLAC] {MFSL 200g vinyl 24-96}: Is a directory
md5sum: David Crosby - If I Could Only Remember My Name... (1971) [FLAC] {Atlantic SD 7302 Vinyl 24-96}: Is a directory
md5sum: dgq1999-05-16.flac16: Is a directory
md5sum: Duane Allman - An Anthology (1972) [FLAC]: Is a directory (1)
It seems to be processing now, but do I have to get an md5 file? I'd rather just verify that the files are ok.