>>I think you're missing TABLE_TYPE = 'BASE TABLE' WHERE condition
>
>What would be a corrected version, in such a case, of the code?

*** INFORMATION_SCHEMA version
USE YourDataBase
DECLARE @TableName AS varchar(8000)
DECLARE @sql       AS varchar(8000)
SELECT @TableName = MIN(Table_Name) FROM INFORMATION_SCHEMA.Tables WHERE TABLE_TYPE = 'BASE TABLE'
WHILE @TableName IS NOT NULL
      BEGIN
          SET @sql = 'DROP TABLE '+@TableName
          EXEC (@sql)
          SELECT @TableName = MIN(Table_Name) FROM INFORMATION_SCHEMA.Tables WHERE Table_Name > @TableName AND TABLE_TYPE = 'BASE TABLE'
      END


*** sys.Tables version
USE YourDataBase
DECLARE @TableName AS varchar(8000)
DECLARE @sql       AS varchar(8000)
SELECT @TableName = MIN(Name) FROM sys.Tables WHERE Type_Desc = 'USER_TABLE'
WHILE @TableName IS NOT NULL
      BEGIN
          SET @sql = 'DROP TABLE '+@TableName
          EXEC (@sql)
          SELECT @TableName = MIN(Name) FROM sys.Tables WHERE Name > @TableName AND Type_Desc = 'USER_TABLE'
      END