You need to be a lot more specific. At what point in the script process does that error get thrown? If it's at the very beginning then you probably have a syntax error in your connection string or something else basic like that. If it's not in the beginning, then it could be due to a load that's too heavy (like a join over millions over records). Take a look at the log file for more details (and make sure you are generating one in Document Properties).
Interesting--so the error is that the ODBC connection is failing. That says a lot, because you know it's not a syntax problem but is almost definitely related to performance. Does your database have logging enabled? Check there and see if maybe you reached some kind of cap. That might actually be the problem since it's failing exactly at 7,000 rows.
I really have no idea, other than it's a DB issue. Did you take a look at the DB's log files to track what is happening during that read? Maybe something changed after 2001 with the way the fields are stored (how many bits) or what they are called...if you have a DB Admin I suggest you talk to them to work on this problem together.