A land deal that promised to pump $2 million into a Prince George's County affordable-housing program has fallen apart, and officials are searching anew for a developer for the last county-owned part of the Collington Center industrial park.

The decision by Linpro Inc. to back out of the $10.3 million land purchase dealt a setback to County Executive Parris N. Glendening, who said last year that the complicated transaction was a "major breakthrough" in the county's efforts to increase the availability of low-cost housing.

As a condition of the purchase, the Philadelphia-based development company agreed to contribute $2.2 million to a special program being set up by the county to help first-time buyers find affordable housing.

In an interview, Glendening said that Linpro's decision to back out of the purchase will not affect the county's pledge to finance new affordable housing programs. He said the county has promised to raise $3.5 million for the effort over the next five years and "we intend to meet that commitment."

But Glendening said he was uncertain whether the county will be able to extract the same contribution from other potential developers of the Collington Center site. "Basically, if we can get someone else to pay the bill, we'll do so," he said.

Development of the 68-acre property was considered the last major step in the completion of the industrial center on Route 301 near Upper Marlboro. A major initiative of the Glendening administration, the center recently has come under scrutiny because of allegations that the county sold land at bargain prices to politically connected developers.

Glendening has defended the development, which still has vacant land and close to 500,000 square feet of empty warehouse space, as a major boon to county tax revenue and employment.

Linpro, which was working in a joint venture with an arm of the Potomac Electric Power Co., won development rights for the southern part of the center by submitting the highest of 10 bids. The venture encompassed plans to build a warehouse and distribution center.

The county engaged in intense behind-the-scenes bartering with Linpro to consummate the deal. One controversial concession was the county's promise to pay Linpro about $5 million to build a police warehouse and printing plant on eight acres of the property.

The county intended to buy back part of the land at $10,000 more per acre than it would receive from the developer. Officials said the higher price would reflect costly improvements Linpro would have to make to the undeveloped land at its own expense.

The county also promised to build a road from Route 301 into the Linpro property, a project expected to cost about $2.5 million.

Some critics on the County Council questioned the arrangements in October 1989 when the plan came before it for approval, including the need for a new warehouse when privately owned warehouse space is available for lease. During the discussions, council members Floyd E. Wilson Jr. and Anthony J. Cicoria also blasted Linpro's affordable housing contribution, calling the promise a "hoax."

The council eventually approved the transaction. But earlier this year, the county decided it could not afford to build the warehouse. Glendening said county officials are devising a new plan for construction of the facility, which he said is desperately needed.

Steven A. Teitelbaum, an attorney for the joint venture, said the Linpro group's contract lapsed in April because the county and the developer could not reach agreement on the warehouse construction.

"The design of the warehouse was purely up to them," he said. "We had an engineer working with them, trying to make it happen. Every time they would put pencil to paper the budget line would move, and finally the price was more than the county felt it could afford."

When Linpro pulled out, Don Spicer, the Collington Center general manager, said the county approached the second highest bidder, a joint venture between Union Pacific Realty and the Colton & Laskin development firm, about submitting a new proposal for the property. He said those discussions also fell through.

Instead, Spicer said the county plans to finish construction of the access road, then begin a new search for a developer.