Compiling a vi with link to an external non NI dll => error 7 "source does not exist""

[eddie grundy fan]

I'm trying to compile a vi using Application Builder. The vi contains a number of links to drdaq32.dll (a dll to give access to Picotech�s DrDAQ data aquisitiion unit. This is connected via the parallel port and comes with a BNC connector and a high impedance input suitable for pH probes). Communication with the dll is via code interface nodes).

System:
LabVIEW v. 6i
Windows NT4
DrDAQ and DrDAQ.dll via parallel port (lpt 1) www.picotech.com
Code interface node calls to the dll use a standard (WINAPI) calling convention and �run in UI thread�

When I try to build, I get the error
"Error 7 occured at ......drdaq32.dll - source does not exist"

The source does exist. I hav
e got the same error with the dll in the same directory as my vi and in a sub directory data.

Why does Application builder refuse to see this file ??

[Labviewguru]

I don't believe that this is the case.

Application builder is really very specific about what files are available and in what state. Though it is not really documented anywhere to my knowledge, the proper steps to building an application are as follows:

Before doing this, LabVIEW should be closed, and all other VIs out of memory.

1. Open your top level VI.
2. Click the run button to recompile
3. Choose "Save All" from the file menu
4. Close your top level VI and ensure that all VIs are saved properly.
5. Quit LabVIEW
6. Open LabVIEW - DO NOT open any of your VIs. Open LabVIEW from labview.exe via the start menu or other shortcut!
7. Open a new VI.
8. Open the application builder (tip, I went into the projects folder and
pulled a shortcut of the app builder out and onto my start menu, this opens the app builder fresh after LabVIEW has been exited.
9. Proceed with your build as normal.

The problem is that LabVIEW retains VIs in memory, even after they are all closed. If there is anything incomplete about these VIs, this will affect the build process. Unsaved VIs do not show up as being valid files (or something like that) to the app builder, thus if you didn't save even one single VI and try to build the application, you will get an error 7.

Step 1 is specific to your case, as recompiling ensures that all external connections are properly made.

If you still have the problem, post here and let us know.