The problems Sheila Zakre of Concord encountered while trying to secure quality home care for her aged mother through a state program could be an aberration. Client satisfaction surveys conducted for care-giving agencies suggest it is, and we certainly hope so. Zakre, whose account appeared in last Sunday's Monitor, described cursory case management, untrained staff, unexpected cancellations and a high turnover rate - 13 different home health care workers in five weeks. The Department of Health and Human Services' "Choices for Independence" program, created to save taxpayers money while allowing the elderly and disabled to stay in their own homes, won't succeed if her experience is common.