ORA-28591: agent control utility: unable to access parameter file
Cause: The agent control utility was unable to access its parameter file. This could be because it could not find its admin directory or because permissions on directory were not correctly set.
Action: The agent control utility puts its parameter file in either the directory pointed to by the environment variable AGTCTL_ADMIN or in the directory pointed to by the environment variable TNS_ADMIN. Make sure that at least one of these environment variables is set and that it points to a directory that the agent has access to.
ORA-28591错误是指无法访问参数文件，官方解释是，这是一个专门的错误代码，对应关联的Oracle单元未能在系统上找到特定的参数文件。
1.检查ORACLE_HOME路径是否对于使用Oracle客户端的用户是可见的。
2.检查系统中是否存在缺少的参数文件（或XML文件），如果有，请将其复制到ORACLE_HOME的/network/admin目录（或任何指定的文件夹）中。
3.检查参数文件（或XML文件）是否设置了不正确的路径。
4.最后，如果以上给出的步骤仍然没有解决问题，可以重新安装Oracle客户端软件，并将正确的参数文件复制到相应的路径中。