Are all the reports deploying to the same folder on the report server?

It isn't clear, at least not to me, if this is an initial deploy or if you are making changes and overwriting existing reports. I'm assuming that you are overwriting existing reports.

1. Can you manage the reports on the report server? Go to the report server, right-click on one of the problem reports and select Manage.

2. Then you can try to upload the RDL directly from there or you can delete the problem reports from there.