Since you posted in the Worksheet Functions gourp,
perhaps something like this:

With A1:D5 containing this list
Error_Summary Count Source_Type_Code Loan_Type
Blank Text 6 C CL
Consolidation 7 C CL
Unique ID 3 C CL
Interest Rate 4 C CL

and...
G1: (an Error_Summary value....eg Consolidation)
H1: (an Source_Type_code value....eg C)
I1: (an Loan_Type value....eg CL)

then..this formula returns the Count associated with that combination
F1:
=INDEX($B$1:$B$10,MATCH(G1&"_"&H1&"_"&I1,INDEX($A$ 1:$A$10&"_"&$C$1:$C$10&"_"&$D$1:$D$10,0),0))

Note: that formula returns an error if there is no match for that
combination.
A formula can be used that will test for a match first....but it will be
very messy.

HOWEVER....if you used a Pivot Table, or even an AutoFilter,
you'd have your answer with practically no work at all.

Does that help?

Post back with more questions.
***********
Regards,
Ron

XL2002, WinXP


"Robert_L_Ross" wrote:

Here's my problem - I have the following table:
Error Summary Count Source Type Code Loan Type
Blank Text 6 C CL
Consolidation 7 C CL
Unique ID 3 C CL
Interest Rate 4 C CL

I need to to a vlookup where I match Error Summary AND Loan Type AND Source
Type Code, then return the Count.

Is this possible?