SQLDA question

I am trying to use the SQLDA to dynamically create SQL statements.  I am
getting the following error when running the program 

                                Message ID . . . . . . :   SQL0822
Severity . . . . . . . :   30         
                                Message type . . . . . :   Diagnostic

                                Date sent  . . . . . . :   06/16/05
Time sent  . . . . . . :   12:26:47   
        

                                Message . . . . :   Address in the SQLDA
not valid.                            
                                Cause . . . . . :   The SQLDA contains
an address, SQLDATA value, or SQLIND    
                                  value in entry number 1 that is not
valid.  The incorrect address or value   
                                  is type 1.

                                    -- Type 1 indicates that the SQLDATA
address is not valid.                 
                                    -- Type 2 indicates that the SQLIND
address is not valid.                  
                                    -- Type 3 indicates that the SQLDA
address is not valid.                   
                                    -- Type 4 indicates that the row
storage area is not large enough.         
                                    -- Type 5 indicates that the
indicator area for a blocked FETCH statement  
                                  is not large enough.

                                    -- Type 6 indicates that the SQLDATA
field was not initialized to a value  
                                  in a REXX procedure 
                                     -- Type 7 indicates that the SQLIND
field was not initialized to a value   
                                   in a REXX procedure.

                                     -- Type 8 indicates that the
SQLDATAL address is not valid.                
                                 Recovery  . . . :   For types 1, 2, 3,
or 8, change the address in entry 1 to  
                                   a valid address. For types 4 and 5,
allocate enough area for all of the rows 
                                   being requested. For types 6 and 7,
initialize the SQLDATA or SQLIND fields  
                                   to a valid value. Try the request
again.                                     
                                 Technical description . . . . . . . . :
When an SQLDA is used on FETCH,      
                                   OPEN, or EXECUTE, the address in each
SQLDATA entry in the SQLDA must be set 
                                   to a valid address.  If the SQLTYPE
value indicates that an indicator        
                                   variable is also provided, the
corresponding SQLIND entry must contain a     
                                   valid address in addition to the
SQLDA being set to a valid address. In the  
                                   case of a REXX procedure, the SQLDATA
and SQLIND fields are not pointers,    
                                    but are buffers containing the
variable and indicator values. When an SQLDA  
                                is used on an OPEN or EXECUTE, these
variables must be initialized to a      
                                valid value.             

                                So, I can tell that I have a problem
with the address in SQLDATA.  I think the error is in reference to my
open statement.  I assume I need to have an eval statement for the
SQLDATA, but I don't have a clue what to put there.... Here is a snippet
of my code.  Any ideas of what I'm doing wrong?  I've also tried it with
sqldabc = 1 * 80 + 16 and sqldabc = 2 * 80 + 16 for the second
occurance.  Same error


                                C                   eval      SQLN = 2

                                C                   eval      SQLD = 2

                                C                   eval      SQLTYPE =
452              
                                C                   eval      SQLLEN  =
1                
                                C                   eval      SQLNAME =
'SAMPLE'         
                                C                   eval      sqldabc =
SQLN*80+16       
                                C                   movea     sqlvar
sql_var(1)   
                                C                   eval      SQLTYPE =
452              
                                C                   eval      SQLLEN  =
1                
                                C                   eval      SQLNAME =
'SAMPLE1'        
                                C                   eval      sqldabc =
SQLN*80+16       
                                C                   movea     sqlvar
sql_var(2)   
                                C/Exec SQL

                                C+        PREPARE SQL_Stmt FROM
:SQL_String              
                                C/End-Exec

        

                                C/Exec SQL  
                                C+        DECLARE SQL_Read SCROLL CURSOR
for SQL_Stmt   
                                C/End-Exec

        

                                C/Exec SQL

                                C+        OPEN SQL_Read Using DESCRIPTOR
:SQLDA         
                                C/End-Exec