Try this:

DECLARE @BegDate datetime

SET @BegDate = NULL

IF @BegDate = NULL

     PRINT 'NULL equals NULL'

IF @BegDate IS NULL

     PRINT 'NULL IS NULL'

ELSE IF...

Can you post a bit more of your data?  I am guessing that things like "query" can vary in length.  Hence, you may have to loop through each line using...

Your procedures look fine.  Can you post your calling code in .NET?  That might be where the problem is occuring. 

I would posit that what you need to do is change the input of your data from:

Sample Data:   frm_ky    FK_vendors   projName

                       1            1,2            project1 

To:

Sample Data:   frm_ky    FK_vendors  ...

The Developer is always ahead?  Is that the joke?    heheee

I think this may be a scope issue.  When you execute sp_ExecuteSQL you start a new SPID; hence the called procedure cannot see the calling procedure. 

You may...

I've read your very helpful and insightful responses for quite some time now, Gift Peddie. 

But I cannot testify to your sanity... 

So Sybil...  What color is the sky in your world?  (All three in one body - can't be good...  do you fight with yourself?) 

Now that's what I was looking for!!! 

Not sure where you are using this field...  If it is within the table itself, look up IDENTITY in BOL.  If it is part of the processing, you can either...

This is rather heavy-handed, but if you have a known number of TOP choices, you could use flow control....

DECLARE @Top tinyint

SET @Top = 2

IF @Top = 1...

Good thinking!     [ Sheesh..., I must 'a left my bulldozer at home.... ]

Are you getting an error?  The conversion should be implicit.  You could always try REPLACE( CONVERT( varchar, GETDATE(), 102), CHAR(46), CHAR(45))

Holy cow!  I did not realize that...  I guess you would have to loop and insert the data into a temp table, (of course, scope then becomes an issue) and...

I think I get you.  Can you wrap the whole thing in sp_executesql?