请问合同协议上的process agent是什么意思？

就是“代理人”啊

代理商

维基百科上面的英文解释是：A process agent is a representative upon whom court papers may be served. Process agents accept service of notices, proceedings or documents on behalf of their overseas clients in situations where it is not possible for them to be served abroad.
由此看来，翻译为“诉讼文件代收人”更为恰当，不能单独译为“代理人”。