ProGet Package Upload step fails in Jenkins

I'm trying to create a Universal Package from Jenkins. When I run the build step, I get the following error:

D:\Jenkins\Acquisition\EOI\EOI_Sep16>exit 0
[ProGet] Packaging Artifacts
ERROR: Build step failed with exception
D:\Jenkins\Acquisition\EOI\EOI_Sep16 does not exist.
at org.apache.tools.ant.types.AbstractFileSet.getDirectoryScanner(AbstractFileSet.java:483)
at org.apache.tools.ant.types.AbstractFileSet.getDirectoryScanner(AbstractFileSet.java:460)
at com.inedo.proget.api.ProGetPackager.getFileList(ProGetPackager.java:208)
at com.inedo.proget.jenkins.UploadPackageBuilder.perform(UploadPackageBuilder.java:174)
at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:785)
at hudson.model.Build$BuildExecution.build(Build.java:205)
at hudson.model.Build$BuildExecution.doRun(Build.java:162)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:537)
at hudson.model.Run.execute(Run.java:1741)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
at hudson.model.ResourceController.execute(ResourceController.java:98)
at hudson.model.Executor.run(Executor.java:408)
Build step 'ProGet Package Upload' marked build as failuretext

But I know that the content is present:

D:\Jenkins\Acquisition\EOI\EOI_Sep16>dir d:\Jenkins\Acquisition\EOI\EOI_Sep16
Volume in drive D is JENWK0D1VND01_D
Volume Serial Number is ACAD-1029

Directory of d:\Jenkins\Acquisition\EOI\EOI_Sep16

09/01/2016 04:29 PM <DIR> .
09/01/2016 04:29 PM <DIR> ..
09/01/2016 04:28 PM 22,787 AllProjects_SONAR.sln
09/01/2016 04:28 PM 256 AllProjects_SONAR.vssscc
09/01/2016 04:28 PM <DIR> Application
09/01/2016 04:29 PM <DIR> Assemblies
09/01/2016 04:29 PM <DIR> Database
09/01/2016 04:29 PM <DIR> Deployment
09/01/2016 04:29 PM <DIR> ExternalDependencies
09/01/2016 04:29 PM <DIR> InstallPackages
09/01/2016 04:29 PM <DIR> Scripts
09/01/2016 04:29 PM <DIR> Tests
09/01/2016 04:29 PM <DIR> Web
2 File(s) 23,043 bytes
11 Dir(s) 17,781,252,096 bytes free

Any ideas what is wrong? Jenkins and ProGet are running on a Windows Server 2012 server.

Product: ProGet
Version: 4.3.1

Hi Stuart

Could you let me know the settings you're using in the upload proget package build step in your Jenkins job and if you've changed any of the default settings in the advanced section of the build step?

I've not been able to come up with a combination that causes an exception to be thrown in UploadPackageBuilder.java.

Regards
Andrew