Fixed typo in error message (#592).

packages/hdnode/src.ts/index.ts

@@ -197,7 +197,7 @@ export class HDNode implements ExternallyOwnedAccount {
                 if (index >= HardenedBit) { throw new Error("invalid path index - " + component); }
                 result = result._derive(index);
             } else {
-                throw new Error("invlaid path component - " + component);
+                throw new Error("invalid path component - " + component);
             }
         }