I've submitted enough bugs to know that my response of 'works on my machine' isn't terribly helpful.  But an error message without some code isn't test-able.

If you have purchased the SDK, you have access to free support.

If not, based on past responses in this forum, Sage Support will recommend that you purchase the SDK, and then contact their support.   

(edit)

I stand corrected.  If what Harjot from Sage Support suggested doesn't help in your situation, please post more information.  I was working on a fully patched Windows 8.1 workstation, so it would have had the latest .NET framework.   According to https://msdn.microsoft.com/en-us/library/hh925568(v=vs.110).aspx running version 4.52 (release 0x0005cbf5 / 379893)

Programming is a hobby for me, so I promise nothing, but you never know, a second pair of eyes and all that...

The minimum I would need to go further would be which SDK version your code was working / not working in, plus the offending few lines of code.  Among the many things I haven't tried in order to reproduce the problem, is to take an old (like 2013.1) c# SDK_Example, move the project to the 2015.3 release and try it there.  

 
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I've submitted enough bugs to know that my response of 'works on my machine' isn't terribly helpful.  But an error message without some code isn't test-able.

If you have purchased the SDK, you have access to free support.

If not, based on past responses in this forum, Sage Support will recommend that you purchase the SDK, and then contact their support.   

(edit)

I stand corrected.  If what Harjot from Sage Support suggested doesn't help in your situation, please post more information.  I was working on a fully patched Windows 8.1 workstation, so it would have had the latest .NET framework.   According to https://msdn.microsoft.com/en-us/library/hh925568(v=vs.110).aspx running version 4.52 (release 0x0005cbf5 / 379893)

Programming is a hobby for me, so I promise nothing, but you never know, a second pair of eyes and all that...

The minimum I would need to go further would be which SDK version your code was working / not working in, plus the offending few lines of code.  Among the many things I haven't tried in order to reproduce the problem, is to take an old (like 2013.1) c# SDK_Example, move the project to the 2015.3 release and try it there.  

 
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