diff --git a/mk2rbc/mk2rbc_test.go b/mk2rbc/mk2rbc_test.go
index 1e53c3071..2d768aeac 100644
--- a/mk2rbc/mk2rbc_test.go
+++ b/mk2rbc/mk2rbc_test.go
@@ -1049,7 +1049,7 @@ def init(g, handle):
   }.get("vendor/%s/cfg.mk" % g["MY_PATH"])
   (_varmod, _varmod_init) = _entry if _entry else (None, None)
   if not _varmod_init:
-    rblf.mkerror("cannot")
+    rblf.mkerror("product.mk", "Cannot find %s" % ("vendor/%s/cfg.mk" % g["MY_PATH"]))
   rblf.inherit(handle, _varmod, _varmod_init)
 `,
 	},
@@ -1073,7 +1073,7 @@ def init(g, handle):
   }.get("%s/cfg.mk" % g["MY_PATH"])
   (_varmod, _varmod_init) = _entry if _entry else (None, None)
   if not _varmod_init:
-    rblf.mkerror("cannot")
+    rblf.mkerror("product.mk", "Cannot find %s" % ("%s/cfg.mk" % g["MY_PATH"]))
   rblf.inherit(handle, _varmod, _varmod_init)
 `,
 	},
@@ -1099,7 +1099,7 @@ def init(g, handle):
   }.get("%s/cfg.mk" % g["MY_PATH"])
   (_varmod, _varmod_init) = _entry if _entry else (None, None)
   if not _varmod_init:
-    rblf.mkerror("cannot")
+    rblf.mkerror("product.mk", "Cannot find %s" % ("%s/cfg.mk" % g["MY_PATH"]))
   rblf.inherit(handle, _varmod, _varmod_init)
   #RBC# include_top vendor/foo1
   _entry = {
@@ -1107,7 +1107,7 @@ def init(g, handle):
   }.get("%s/cfg.mk" % g["MY_PATH"])
   (_varmod, _varmod_init) = _entry if _entry else (None, None)
   if not _varmod_init:
-    rblf.mkerror("cannot")
+    rblf.mkerror("product.mk", "Cannot find %s" % ("%s/cfg.mk" % g["MY_PATH"]))
   rblf.inherit(handle, _varmod, _varmod_init)
 `,
 	},
diff --git a/mk2rbc/node.go b/mk2rbc/node.go
index d38299d34..ebc57b23b 100644
--- a/mk2rbc/node.go
+++ b/mk2rbc/node.go
@@ -110,7 +110,9 @@ func (i inheritedDynamicModule) emitSelect(gctx *generationContext) {
 		gctx.writef("if not %s:", i.entryName())
 		gctx.indentLevel++
 		gctx.newLine()
-		gctx.write(`rblf.mkerror("cannot")`)
+		gctx.write(`rblf.mkerror("`, gctx.starScript.mkFile, `", "Cannot find %s" % (`)
+		i.path.emit(gctx)
+		gctx.write("))")
 		gctx.indentLevel--
 	}
 }