"Multiple-step OLE DB ... errors" on ADO PutValue

[VC++ 6.0, SQL Server]
I get the this error when I execute the last line of the following code:

"Multiple-step OLE DB operation generated errors. Check each OLE DB value, if available. No work was done."

Code:

---

CString csState = "MA";
BYTE* bt = new BYTE [256]
        for (int i = 0; i < 256; i++)  //my initialization for testing
        {
                bt[i] = i + 1;
        }
BSTR bstrBuff = SysAllocStringLen((LPOLESTR)bt,256);

pRst->Fields->GetItem("state")->Value = (_bstr_t) csState;
pRst->Fields->GetItem("data")->Value = bstrBuff;

---

The assignment of 'state' [varchar(2)] is OK. When csState has 3 characters, I get the same error.

A recurring theme in the forum(s) for this error around this kind of operation is:
the value is not suitable for the field to store.

The database field 'data' is declared as varchar(600). I also tried varbinary(600).

So, I am at a loss for an explanation.

Thanks for any thoughts,

jim

EDIT: corrected the bug in my code example.
Perhaps a buggy example doesn't warrant a response. :blush:
I am completely stalled on this.
Does any body have an idea?
Thanks,
jim

Here is some additional info:

Based on some further research, I've updated my code sample (including bug fix) as follows:

Code:

---

BYTE* bt = new BYTE [256];
        for (int j = 0; j < 256; j++)  //my initialization for testing
        {
                bt[j] = j + 1;
        }
BSTR bstrBuff = SysAllocStringByteLen((LPCSTR)bt,256);

_bstr_t bstrt(bstrBuff );
int bstrLen = bstrt.length();  //this is 128

pRst->Fields->GetItem("TData")->Value = bstrt;

---

Also, here's the definition of the 'TData' field

[TData] [varchar] (600) NULL

But I still get the error:

"Error number: 0x80040e21
Multiple-step OLE DB operation generated errors."

The field accepts NULLs if for some reason bstrt was NULL. The field should have plenty of space for the BSTR of size 128. [And as I mentioned before I also tried varbinary(600).]

I've also looked at the memory of bstrBuff and bstrt in the debugger and they both seem like well formed BSTRs with the expected initial values.

Can anybody give me a clue as to why I'm still getting this message? I'm really brick-walled here.

Humble thanks,

jim

For anyone who may be interested in the resolution to this problem:

I received from invaluable help from Krzemo in the CodeGuru Database forum.

I was told that although BSTR can contain binary values, it cannot be used to store binary values into a database. And that seems to have been the reason for the error message.

I was advised to convert my BYTE* array to SAFEARRAY and use the SAFEARRAY to write to/read from the database.

To convert to/from BYTE* and SAFEARRAY, I adapted code from the sample in

http://www.codeproject.com/database/...select=1608797


All seems to be well.

jim