.fseventsd .Sportlight-V100 .TemporaryItems .Trashes

.fseventsd is part of the File System Events notification mechanism - when a file changes, the operating system sends a message to any programs which care, such as the Spotlight indexing system.

.Spotlight-V100 is where Spotlight keeps its index data: when you search in Spotlight, it looks in this index rather than searching all the files directly.

.Trashes store deleted data (one directory per user inside that, IIRC).

Normally all these files/directories are hidden; if deleted, OS X will re-create them automatically. (In Spotlight's case, this can take a while: it will have to read all the files on the disk to re-index them.)

Are those problem applications you mention older ones? From the sound of it, they are written for PowerPC - so the newer Intel based Macs, such as all MacBooks, need the Rosetta translation software to be able to run them. (Before Snow Leopard, Rosetta came built in; after Snow Leopard, it was discontinued.) It's also possible to force dual-platform binaries to run under Rosetta instead of running natively, by ticking that box in the application's properties window in the Finder.