Cash-strapped, drug-addled Robert Harrison - an ex-star Merrill Lynch stockbroker - hatched the plot to lure 21-year-old James Weichert Jr. to a graveyard in Morris County last week and then nab him to extort his parents, officials said.

But Harrison, 38, was foiled after James Jr. became suspicious when the disgraced money manager called his cellphone and lied that he was a detective from the "New Vernon Police Department," authorities said.

Harrison allegedly told the son, whose family is from New Vernon in Harding, that a Mercedes-Benz had been found abandoned at the cemetery, with paperwork inside linking it to him. Harrison suggested that the young man meet him at the site, officials said.

The only problem is, there is no New Vernon Police Department.

Smelling a rat, the quick-thinking heir called his dad, and authorities were immediately alerted.

Cops later found duct tape, a BB gun and a ransom note demanding "a large amount" of money in the trunk of Harrison's black 1994 Mercedes, authorities said.

Harrison — a married dad of two young boys and admitted cocaine and heroin addict — had been fired as Weichert's personal financial adviser in October 2000, officials said.

He was booted by Merrill Lynch a year later, after customers griped he was making unauthorized trades and charging them inflated fees, The Star-Ledger of Newark said.

Harrison, in a jail interview, told The Star-Ledger that he had been raking in up to $1 million a year as a stockbroker, but that drugs were part of his downfall.

"The whole thing is a complete, complete mistake," Harrison said of his bust. "I'm not some crazed person who is going to kidnap someone.

"Did I have some stupid thoughts? Yes," the alleged kidnapper wannabe told the paper. "[But] I did not even come close to acting on it."

In pleading with a judge yesterday to reduce his $200,000 bail, Harrison whimpered, "I really am a good person at heart."

Harrison told The Star-Ledger that financial woes forced him and his family to move from a million-dollar pad in Maplewood to a small rental house in Monmouth Beach seven months ago.

One source who knows Harrison said last night that he wasn't too surprised at the bust.

"He's a bit strange," the source said. "He smoked a lot of cigarettes and definitely had a nervous edge.

"He was always in his car. It was bizarre," the source added. "He liked sitting in the car making phone calls, always with the trunk open. He was always fiddling around talking as the kids were [going] in and out."

But neighbor Joe Jackson called Harrison's alleged plot "very out of character.

"He's never cruel, and there haven't been mean words of any kind," Jackson said. "He's very happy-go-lucky. He seems super-intelligent."

Lt. Jeffrey Paul, spokesman for Morris County Prosecutor Michael Rubbinaccio, praised the Weicherts, saying, "We credit the family with their prompt response in handling the situation."

Additional reporting by Steven Hirsch