ORACLE PL/SQL: Table or view does not exist - oracle

Question

I'd appreciate some help on this topic since I am making my first steps into PL/SQL:
When trying to create a function, I get an error: "Table or view does not exist" for all 5 Select statements (and for the statement in the cursor declaration as well). I am sure all tables exist.
Many thanks in advance.
CREATE OR REPLACE FUNCTION ZINSKALK (vtid IN NUMBER, intart IN INTEGER)
RETURN NUMBER
IS
j INTEGER := 0;
p NUMBER := 1;
q NUMBER := 0;
t NUMBER := 1;
r NUMBER := 0;
lz INTEGER := 0;
modusvn INTEGER := 0;
w1 NUMBER := 0;
w2 NUMBER := 0;
i INTEGER := 0;
TYPE ARRAY_TYP IS VARRAY (200) OF NUMBER (10, 2);
RARRAY ARRAY_TYP;
CURSOR C1
IS
SELECT vtobslpos.anzahl, vtobslpos.betrag
FROM vtobsl, vtobslpos
WHERE vtobsl.sysid = vtobslpos.sysvtobsl
AND vtobsl.sysid IN
(SELECT MAX (vtobsl.sysid)
FROM vtobsl
WHERE vtobsl.sysvt = vtid AND vtobsl.rang = 100)
ORDER BY vtobslpos.rang ASC;
BEGIN
SELECT SUM (vtobslpos.anzahl)
INTO lz
FROM vtobslpos, vtobsl
WHERE vtobslpos.sysvtobsl = vtobsl.sysid
AND vtobsl.sysvt = vtid
AND vtobsl.sysid IN (SELECT MAX (sysid)
FROM vtobsl
WHERE sysvt = vtid AND rang = 100);
SELECT vtobsl.modus
INTO modusvn
FROM vtobsl
WHERE vtobsl.sysid IN (SELECT MAX (sysid)
FROM vtobsl
WHERE sysvt = vtid AND rang = 100);
SELECT bgextern
- sz
+ (CASE intart
WHEN 1 THEN 0
WHEN 2 THEN - (sz2 + disagio)
WHEN 3 THEN (sz2 + disagio - provision)
ELSE 0
END)
INTO W1
FROM vt
WHERE sysid = vtid;
SELECT rw + rsv
INTO w2
FROM vt
WHERE sysid = vtid;
i := (CASE WHEN modusvn = 0 THEN 1 ELSE 0 END);
RARRAY (1) := -w1;
RARRAY (lz + 1) := w2;
FOR x IN C1
LOOP
FOR y IN 1 .. x.anzahl
LOOP
i := i + 1;
RARRAY (i) := RARRAY (i) + x.betrag;
END LOOP;
END LOOP;
WHILE ABS (p) >= 0.001
LOOP
p := 0;
q := 0;
j := 0;
FOR z IN 1 .. lz + 1
LOOP
j := j + 1;
p := p + RARRAY (j) * POWER (t, j - 1);
q := q + (j - 1) * RARRAY (j) * POWER (t, j - 2);
END LOOP;
t := t - p / q;
END LOOP;
r := 1200 / t - 1200;
RETURN r;
EXCEPTION
WHEN OTHERS
THEN
RETURN 0;
END;

Answer 1

I assume the table belong to another schema than the schema into which your function is compiled. If you have granted select on these table via role rather than directly, Oracle will give you an ORA-00942.
See this stackoverflow question for more information.

Answer 2

Did you compile the procedure on the same schema of the tables? If you use toad try to press F4 button when cursor is on table name or try to launch the command "desc tablename"

Answer 3

Try describing the tablename with same credentials in the same schema with which you are trying to compile/execute the function.
desc tablename