Load error: undefined path variables (cryptic name)

Hi folks,

Each time I open my project, IDEA complains about "Load error: undefined path variables, fe9b1aed1cdf1dc0f7a4.dex is undefined. "

I don't know what this variable comes from. If I remove it, it appears again at next IDEA startup.

With a grep, I found this variable in 

.idea/modules/dex-woda-build.iml:<module external.linked.project.id="dex-woda-build" external.linked.project.path="$MODULE_DIR$/../../dex-woda/project" external.root.project.path="$MODULE_DIR$/../.." external.system.id="SBT" sbt.imports="$fe9b1aed1cdf1dc0f7a4.dex$minuscommon, $fe9b1aed1cdf1dc0f7a4.dex$minusconnectors, $fe9b1aed1cdf1dc0f7a4.dex$minusserver, $fe9b1aed1cdf1dc0f7a4.dex$minuswoda, $fe9b1aed1cdf1dc0f7a4.root, _root_.play.sbt.Play.autoImport._,  ...

But I don't understand anything of this iml file.

What is it this variable for ?