No worries.
java.lang.NoSuchMethodError: com.fs.starfarer.api.campaign.ai.CampaignFleetAIAPI.performCrashMothballingPrio rToEscape(Lcom/fs/starfarer/api/campaign/FleetEncounterContextPlugin;Lcom/fs/starfarer/api/campaign/CampaignFleetAPI;)V
at exerelin.plugins.ExerelinFleetInteractionDialogPluginImpl.optionSelected(ExerelinFleetInteractionDialogPluginImpl.java:382)
at com.fs.starfarer.ui.O0OO.Q$1.super(Unknown Source)
Yeah, seems the most likely thing, but also seems like *something* on your end is probably out of date, since it's not finding a core method that's there.
... oh, I know what it is. The method signature was changed in the hotfix, and it now takes a FleetEncounterContextPlugin instead of a FleetEncounterContext. So, right bug in Exerelin caused by a change in the hotfix.