NinjaSk8ter

...isnt Null is whats coming in from the application (DBNull)? 

No. You sent NULL to the stored procedure (as @pProjId). In the SP you have 

if @pProjId = null
    begin
    insert into hip_Project (ProjectName, ProjectDesc, ProjectNotes, dtCreated)
    values (@pProjName, @pProjDesc, @pProjNotes, @pProjDate)
    end
else
...

which means that if @pProjId is NULL then SP will insert new entry into the hip_Project table.

As we can see, there is no value specified for the Project_Id column, which means that 

1. either this column should accept NULL 
2. or it should be an identity column that is made up of values generated by the database.

Now, see the code below

if @pProjId = null  
    SELECT SCOPE_IDENTITY() as newProjectID  
else  
...

This tells me that it is expected to get a value from the SCOPE_IDENTITY function which returns the last identity value inserted into an identity column in the same scope. As there is only one INSERT statement - it means that the the Project_Id column should be an identity column and not NULL.