If it is a regular poster, and they are still posting then I would think that it is possible that the e-mails could be going astray and not reaching them. Maybe you could just post on the forum and let them know that you have been trying to reach them.
If it is someone that hasn't been around for a while then maybe something has happened....could be off the computer, or changed their e-mail address or are away...hopefully nothing bad.
You have certainly kept up your end of the deal though.

so...........now we will be watching your list to see what it is!! haha!
Lois

I agree with Lois's comments above.

I would also agree. You have given the trader lots of notice and since you can't predict when this person might be back in action, you should offer the seeds up for trade. She can always catch up with you at a later time if something is keeping her out of action.
AM

I agree that you have made every effort to contact this individual and so you shouldn't feel guilty about going ahead and trading them with someone else.

I have been having issues contacting people lately. Not sure if it is that my e-mails are not reaching them or if they are just getting them and not responding. There are two individuals who contacted me about trades, but when I sent back mail, I'm not getting answers back. I know it can be very frustrating, but there's only so much you can do and then it's time to move on.

Thank you ladies, for your comments. My first contact with this lady was via e-mail from the Canadian Winter Sowing Forum, so I had a valid e-mail address and we did communicate a few times. I also did a search on her e-mail address but that is perhaps not her Forum moniker. I just looked over the e-mails I saved from her and realized that she lives in the same city as I do. Perhaps if she likes, she can have a few of my extra plants - they tend to grow into the grass by underground runner - that's how I got my patch started. I will 'guiltlessly'offer them for trade.
Northerner.