I do not know the reasons for the delay. I suspect is a red tape. Everything went fine to the interview. And after this I am waiting for the oath forever. I sent a letter to the INS center in Dallas at the end of June. Never got a reply. Then at the end of July I called the national 1-800 number. They could not tell me anything about the reasons for the delay. They said that the reasons are without the Dallas center. They took my information and send an inquiry to Dallas. Three weeks later I received a standard letter stating "The status of your claim is: Your case is currently pending schedule for an Oath Ceremony". That was around Aug.20. Still nothing. In early October I went to 2 congressemens' offices. The first refused to make an inquiry because I wasn't in his district. So I went to the congressman representing my district. They took my package (a letter stating my situation, copies of my notice of action, fingerprint form,interview results, status inquiry letter) and told me it will take 30 days after INS receive their request. This was on Oct 8. So I plan to contact them next week.
I am not the only one having this problem. There was a group of people that had their interviews between Oct.2002 -March 2003 that have problems with the oath ceremony letter. My guess is that when in March INS went into the Bureau of Homeland Security we fall in a bureaucratic black hole. Meanwhile they are giving oath dates to people that had an interview in September. Some of them have been scheduled for an oath ONE WEEK after their interview. I am very frustrated.
As for me, I don't have anything that can create a problem. Not from a problem country, never had even a traffic ticket, been only once out of the country in the past 10 years, married to a US citizen for 10 years, came as lawfull permanent resident.