I get the error on the db and DBHelper saying "Cannot make a static reference to the non-static field db" and "Cannot make a static reference to the non-static field DBHelper".

1 quick fix available
change the modifier of db to static and change the modifier of DBHelper to static

Code:
//DBAdapter.java
package database.create;


import android.app.Activity;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;


public class DBAdapter extends Activity {

		public static final String KEY_STDID = "_ID";
		public static final String KEY_FNAMEID = "FNAME";
		public static final String KEY_LNAMEID = "LNAME";
		public static final String KEY_DOBID = "DOB";
		public static final String KEY_HEIGHTID = "HEIGHT";
		public static final String KEY_WEIGHTID = "WEIGHT";
		private static final String TAG = "DBAdapter";
		
		private static final String DATABASE_NAME = "HEALTHCARE";
		private static final String DATABASE_TABLE = "PHYSICAL_FITNESS";
		private static final int DATABASE_VERSION = 1;
		
		public static final String DATABASE_CREATE = "create table PHYSICAL_FITNESS (_id integer primary key," 
			+ "fname text not null, lname text not null," +
			" d.o.b integer not null, height integer not null," + "weight integer not null); ";
		
		private final Context context;
		private DatabaseHelper DBHelper;
		private SQLiteDatabase db;
		
		public DBAdapter(Context ctx) {
			this.context = ctx;
			DBHelper = new DatabaseHelper(context);
					}
		

		private static class DatabaseHelper extends SQLiteOpenHelper
		{
			DatabaseHelper (Context context)
			{
				super(context, DATABASE_NAME, null, DATABASE_VERSION);
			}
			
			public void onCreate(SQLiteDatabase db)
			{
				db.execSQL(DATABASE_CREATE);
			}
			public void onUpgrade(SQLiteDatabase db, int oldVersion, 
                    int newVersion) 
			{
				Log.w(TAG, "Upgrading database from version " + oldVersion 
						+ " to "
						+ newVersion + ", which will destroy all old data");
				db.execSQL("DROP TABLE IF EXISTS physical_fitness");
				onCreate(db);

		}
			
			public DatabaseHelper open() throws SQLException 
			{
				db = DBHelper.getWritableDatabase();
				return this;
			}
			
			public void close()
			{
				DBHelper.close();
			}
			public long insertphysical_fitness (String _id, String FNAME, String LNAME, String DOB, String HEIGHT, String WEIGHT)
			{
				ContentValues initialvalues = new ContentValues();
				initialvalues.put(KEY_STDID,_id);
				initialvalues.put(KEY_FNAMEID, FNAME);
				initialvalues.put(KEY_LNAMEID, LNAME);
				initialvalues.put(KEY_DOBID, DOB);
				initialvalues.put(KEY_HEIGHTID, HEIGHT);
				initialvalues.put(KEY_WEIGHTID, WEIGHT);
				return db.insert(DATABASE_TABLE, null, initialvalues);
				
			}
			
			public boolean deleteTitle(long rowID){
				return db.delete(DATABASE_TABLE, KEY_STDID + "=" + rowID, null) > 0;
				
			}
			public Cursor getAllTitles() 
		    {
		        		
		        		return db.query(DATABASE_TABLE, new String[] {
		        		KEY_STDID, 		        		
		        		KEY_FNAMEID,
		        		KEY_LNAMEID,
		                KEY_DOBID,
		                KEY_HEIGHTID,
		                KEY_WEIGHTID}, 
		                null, 
		                null, 
		                null, 
		                null, 
		                null);
		    }

		    //---retrieves a particular title---
		    public Cursor getTitle(long _Id) throws SQLException 
		    {
		        Cursor mCursor =
		                db.query(true, DATABASE_TABLE, new String[] {
		                		KEY_STDID,
		                		KEY_FNAMEID, 
		                		KEY_LNAMEID,
		                		KEY_DOBID,
		                		KEY_HEIGHTID,
		                		KEY_WEIGHTID
		                		}, 
		                		KEY_STDID + "=" + _Id, 
		                		null,
		                		null, 
		                		null, 
		                		null, 
		                		null);
		        if (mCursor != null) {
		            mCursor.moveToFirst();
		        }
		        return mCursor;
		    }

		    //---updates a title---
		    public boolean updateTitle(long _Id, String FNAME, 
		    String LNAME, String DOB, String HEIGHT, String WEIGHT) 
		    {
		        ContentValues args = new ContentValues();
		        args.put(KEY_FNAMEID, FNAME);
		        args.put(KEY_LNAMEID, LNAME);
		        args.put(KEY_DOBID, DOB);
		        return db.update(DATABASE_TABLE, args, 
		                         KEY_STDID + "=" + _Id, null) > 0;
		    }
		}	
}