I have now the same problem as you had. In my case Im running Gaussian linear mixed models and after a while, I get the same error: Error in dredge(lmm1, rank = "AICc", REML = F, trace = T) : result is empty.
Additionally, I get warnings like: "missing values in object (model 2095103 skipped)"
Could you solve this in the end? If so, could please share how?