what are dat-####.zip files

We have a computer with bunch of dat-####.zip files (#### is 4 digits number, like 5363, 5364, 5380 ext)under C:\document and settings\all users\application data\network associates\common framwork\current\uscandat 1000\ folder, those files occupied 5.3GB space, what are these files, is that ok to delete them? Please give some advices. Truly appreciate. Thanks!