indirect addressing and pointing a DB with pointer

Hi,
I have a problem with addresses of a DB.
I have two DBs. In one(DB 10) I keep the address of the element from the second one(DB1000). What I want to do is to set a pointer on the element in DB1000 and than to do something with this element. In this case it is setting a bit. Something goes wrong and I cannot set this bit. I base on the S7Guy's program. As an attachement I attach my project.

Setting a bit is done with instructions:
L P##Zeiger
LAR2
S [AR2,P#0.0]

Zeiger keeps the address of the element from DB1000. At least it schould.(How can I know which address is stored in Zeiger? I mean the address of which DB, if I look into AR2 I can see only ie. 4.0, but byte 4 can be in every DB, so how can I be sure in which DB it is?)

What is the difference if I open a DB with instruction
auf DB
or I point at this DB with pointer and then I do sth with elements in ths DB? Is it possible at all to do sth with DB without opening it by using an instruction AUF DB?

You must open the correct DB as the address register only contains the offset and the data area.

And is there a possibility to store an address which points onto the DB and the address in this DB?

A "pointer" variable allows you to store the DB and the area pointer.