Undated (AP) _ Jackie Grant, a 12-year employee of Georgia Power Co., fell ill and took a short-term leave. Two weeks later, Grant says, her boss began threatening to fire her. A few weeks afterward, she quit.

Grant's story offers some insight into the misunderstandings surrounding the Family and Medical Leave Act, which in her view should have protected her job but didn't. The law was enacted a year ago this week.

Hailed by supporters as a milestone for American workers' rights, the law hasn't worked as well as envisioned.

It was designed to guarantee the employment security of people who need emergency time off to care for dependents or for themselves if they are too ill to perform their work. But the law doesn't apply to everyone and contains numerous restrictions.

Even the Labor Department, which enforces the law, says many employees still are unaware of what's covered under it, and many employers are either ignorant or unwilling to comply.

''The law has been tremendously important,'' said Ellen Bravo, executive director of 9 to 5, National Association of Working Women. ''But it's not working for enough people.''

In a survey by 9 to 5, only 46 percent of respondents said information about the leave law was posted at their work place, even though posting is required. Sixty-three percent of those who had taken leave reported problems with their employers concerning misinformation about the law's provisions or their rights.

In Grant's case, the misunderstanding appeared to be on her part. She took leave on the advice of a psychologist for what was described as acute work- related stress. Then, she said, the threats began.

After six weeks she resigned, when Georgia Power told Grant in a letter she risked losing her job.

''I wasn't aware of the Family Medical Leave Act or that I had any rights in that regard,'' Grant said.

Georgia Power spokesman Mike Tyndall said the company had posted information about the law, as required, and publicized it in an internal newsletter. Moreover, Tyndall said, the company had unsuccessfully sought to reach Grant numerous times for documentation to support her leave request.

He also said Grant never asserted until quitting that she had sought leave under provisions of the law. The Labor Department determined last May that Georgia Power had complied.

Still, the episode reflects how unevenly the law has taken hold. Many businesses still don't understand it.

''We've spent most of the year trying to educate our members about who is covered and what they need to do to comply,'' said Mary Reed, legislative representative with the National Federation of Independent Business, a lobbying group in Washington. ''There has been a lot of confusion.''

The law requires that employers continue paying health-care premiums during an employee's leave and give the employee back the same job or an equivalent position. But only about half the nation's workers are covered because small businesses - those with 50 or fewer workers - are exempt.

Despite the shortcomings of the law, Labor Secretary Robert Reich said in an interview that the measure is still important for employees who need to take an unpaid leave because of a family emergency.

''Workers should not have to choose betwen a job and their parents or children,'' he said.

Over the year, the Labor Department has completed investigations of 965 employee complaints relating to the law. Of these, 61 percent were determined to be violations. Usually, employers either refused to return employees to their same or equivalent jobs or refused to grant leave.

Still, more than 90 percent of the complaints were settled with relative ease once employers understood their obligations, Reich said.

Even if employees know their rights, they often don't challenge a company because they're unwilling to risk dismissal and a struggle to get their job back, Bravo said.

''If they need leave they are in a stressful situation,'' Bravo said. ''They don't need to be worried about their job, too.''