You get this response if you have done a mission for this agent within the past 20 hours. Starting the R&D off also counts as the start of a mission, I think. If this agent is in the research tab of your journal, then try again in 20 hours (or after you have received the email from the agent saying that there is a problem - there isn't a problem, but these guys like to be overly dramatic.)
If the agent is not in your journal then you need to find a different agent that you have standings for. The way to do this is to open the agent's show info tab, then click on his corporation. Navigate to the corporation's Agents tab, and expand the R&D section. This section tells you which agents you have the required standings for, and those that you don't. If you then "show info" on the agents that you do not have standings for, you can view their details and it tells you what skills and standings are required.