Blog of the Legal Times explains that Congressman Issa is upset with a biglaw associate who sent an email to Congressional staffers requesting that a client of the firm not be questioned by Congress: "“If possible, please do not direct questions to Jonathan Silver…He’s a client of my firm. :)”
The news account suggests that members of Congress view that as obstruction and a disciplinary matter. If the request was not accompanied by monetary inducement (as it appears it was not), and if there was no threat (as it appears there was not), why would it be improper to ask Congress, "if possible, please don't question me or [so-and-so]"? Whether or not it's prudent to provoke powerful members of Congress, what was wrong with that email?