Versioning error when creating a Topology on a File GDB

Question

Im having an issue with the 99999 Error. Im creating a Topology dataset for each of the featureclasses within a GDB. For some reason my script works for some feature classes and errors on others. I was having an issue with the "add rules" tool, and switched background processing off, which seemed to have fixed that error. However, I now get this unknown error...

Cannot register as versioned on this database. Failed to execute (AddRuleToTopology).

Has anyone had this issue before, before I go and log this with ESRI?

My script:

ws = arcpy.env.workspace = workspace
fc = arcpy.ListFeatureClasses()
log_write("starting to create topologies for {}".format(workspace))

for f in fc:
    fc_name = arcpy.Describe(f).name[4:]
    log_write("creating topology for {}".format(fc_name))

    sr = arcpy.Describe(f).spatialreference
    log_write("spatial ref : {}".format(sr.name))

    input_dataset = arcpy.CreateFeatureDataset_management(ws, "{}_dataset".format(fc_name), sr)
    log_write("dataset created")

    new_fc = arcpy.FeatureClassToFeatureClass_conversion(f, input_dataset, fc_name)
    log_write("added fc to feature dataset")

    topo = arcpy.CreateTopology_management(input_dataset, "Topology", 0.001)
    log_write("topology created")

    arcpy.AddFeatureClassToTopology_management(topo, new_fc, 1)
    log_write("fc added to toplogy")

    arcpy.AddRuleToTopology_management(topo, "Must Not Have Gaps (Area)", new_fc)
    arcpy.AddRuleToTopology_management(topo, "Must Not Overlap (Area)", new_fc)
    log_write("rules added to topology")

    arcpy.ValidateTopology_management(topo)
    log_write("topology validated")