Multivariate fitting with structure fit function in 64-bit Igor

I am doing curve fitting of large data sets using a multivariate, all-at-once, structure fit function. Given the size of the data set, I would like to use the 64-bit version of Igor. I can use the basic form of FuncFitMD; however, when I implement either a destination wave or a weight wave I get the following errors.

When using weight wave:
Error during curve fit: Weight data does not match Y data (length or number type)

When using destination wave:
Error during curve fit: Destination wave does not match Y wave (length or number type)

In both cases, the weight or destination wave are identical in size, type, scaling, etc. to the Y data wave. Works perfectly in 32-bit version of Igor.

Is there some subtlety I'm missing here for working in 64-bit mode? Or is this a bug in the 64-bit version?
On the face of it, it sounds like a bug. That's quite a pile of less-used options: all-at-once, structure fit function, multivariate, Igor64...

Please post an Igor experiment containing everything I need to reproduce it. If it's big, and you can boil it down some, that would be a help.

John Weeks
WaveMetrics, Inc.
support@wavemetrics.com
Ok, here is a compact version of the experiment. You can look at the last two function calls - one was done in 32-bit and worked, the other was in 64-bit and gave the same error as I described. Let me know how it goes, and if you need anything else from me.

Thank you for providing the example of the problem- it was very helpful. You have, indeed, found a bug affecting only 64-bit builds. Tomorrow you can get a replacement of the Igor64.exe executable from the nightly build:

http://www.wavemetrics.net/Downloads/latest/

Be sure to get the Igor64.exe download near the bottom of the page.

Thank you again for your report and the help in tracking down the problem.

John Weeks
WaveMetrics, Inc.
support@wavemetrics.com