Database table locking in SQL Server

Hi, I'm writing a program that use RDO connecting to SQL Server 6.5. I found that some of the tables were
locked when the program was still running. I then step traced my program. After the BeginTransaction
statement, I wrote a SQL statement to drop a database table in SQL server. It's found that some of the tables
were locked after excuting this statment. Since the transaction was not commited yet, only that table being
deleted should be locked. However, this was not the case.
Well, I already have closed the recordset and set it to Nothing before going to other procedure. Also, SQL
Server login do has the Drop permissions on that table. However, still some of the tables are locked. Beside,
same thing happened when creating table instead of dropping table. I'm looking forward to getting help. Thx