Answer by Joshua Eric Turcotte for What does the error "arguments imply differing number of rows: x, y" mean?

Though this isn't a DIRECT answer to your question, I just encountered a similar problem, and thought I'd mentioned it:

I had an instance where it was instantiating a new (no doubt very inefficent) record for data.frame (a result of recursive searching) and it was giving me the same error.

I had this:

return(  data.frame(    user_id = gift$email,    sourced_from_agent_id = gift$source,    method_used = method,    given_to = gift$account,    recurring_subscription_id = NULL,    notes = notes,    stringsAsFactors = FALSE  ))

turns out... it was the = NULL. When I switched to = NA, it worked fine. Just in case anyone else with a similar problem hits THIS post as I did.