Transitive Verbs Requiring a Preposition?

Hi everyone.

MS Word is giving me a verb confusion error over how I'm using the word "whelped." The error is saying I can't put a direct object immediately after this verb. I looked up the definition online and found Google's sample sentence uses it the same way I'm trying to use it:

"Copper whelped seven puppies."

This sounds right, but MS Word isn't happy there's a direct object following whelped and wants me to add a preposition between them. I could understand that rule if it had to look like the following:

"Copper whelped in May."

That sentence makes sense to me, but I don't know why I'm getting an error for the first usage. Even the Encarta Dictionary inside MS Word is saying the verb is both transitive and intransitive, so shouldn't that mean both are correct?

I think this might be a case where my word processor is confused, but I'd like to know if there's anything I'm missing.

Thank you all.

I wasn't sure if I was dealing with some obscure grammar rule, but I tested it on a newer version of Word and didn't get that error. I should probably look into getting a better word processor.