One of the chief installers of fiber-optic cable for the new America Online Inc. data complex in Prince William County was ordered to stop work this week after utility officials claimed that the telecommunications company did not have the proper permits.

The installation, which had a completion deadline of tomorrow, is part of AOL's much-heralded $520 million computer center, which is slated to open in the spring. County supervisors have touted AOL's center as an economic development triumph for Prince William. The data center will be the largest private investment in the county's history, projected to bring about $3.5 million in annual revenue.

MCIMetro Access Transmission Services of Virginia Inc., a subsidiary of MCI WorldCom, was told Wednesday by the Northern Virginia Electric Cooperative to stop installing fiber-optic cable on its poles along Routes 234 and 29. In response to a court challenge issued by MCIMetro, Novec officials alleged that MCIMetro did not obtain proper permits for attaching the cables to 151 Novec utility poles. On Wednesday, Circuit Court Judge LeRoy F. Millette Jr. suspended a previous order that allowed MCIMetro to temporarily continue its work and set a trial date for Nov. 16 to resolve the dispute.

AOL spokesman Andrew Weinstein said that the MCIMetro contract dispute likely will not affect AOL's planned launch date for the computer center. He said AOL officials were unclear about the details of the case.

"Because we use multiple vendors, it shouldn't affect our opening date," Weinstein said, referring to AOL's use of several telecommunications companies for fiber-optic installation. Weinstein said the project is on schedule to open next spring.

Attorneys for MCIMetro and Novec declined to discuss details of the dispute, which focuses on a contract between the two companies. MCIMetro says it received permits from Novec to install fiber-optic cable on 151 utility poles that lead into AOL's new complex, while Novec says those permits are invalid.

MCIMetro began installing the cable on Novec's utility poles in early September, and company officials were told last week that their permits were not valid, said H. Jan Roltsch-Anoll, an attorney representing MCIMetro in the dispute. Court documents indicate that the two companies entered into an agreement in August 1996, under which MCIMetro would apply for permits before attaching cables to a specific pole.

"It's our position that valid permits were issued for these poles, and it is now Novec's assertion that there is something wrong with the permits," Roltsch-Anoll said. "They claim the permit they gave was incorrectly done. It's not an error we made; it's an error that they made."

Roltsch-Anoll said that all work has stopped on MCIMetro's part of the project, and that Novec's stop order is forcing the company to miss a deadline and could jeopardize its relationship with AOL.

Douglas J. Behr, Novec's attorney, said yesterday that the dispute arises out of a misinterpretation of paperwork. Behr said that MCIMetro simply did not have permission to do the project.

"The question is that they say we gave them permission to attach to our poles, and we say we didn't," Behr said. "It's a dispute as to whether they were operative validly issued permits."

Novec, a community-based electric cooperative, owns the utility poles and the surrounding easements, with the exception of segments that travel through Manassas Battlefield National Park. Utility companies regularly sell space on their poles for other commercial uses, including fiber-optic cable for telecommunications services, Internet access or wireless phones.