Try the following workarounds:
WORKAROUND 1
1. Alter system flush shared pool.
2. Start post
WORKAROUND 2
Let SharePlex connect via SQLNet rather than Oracle bequeath connection.
To run as SQLNet, please do the following on the target.
1. Shutdown on target
2. Run ora_setup, make sure to do the following when asked for "SYSTEM" password. When ask for system password, enter the password with @<SID>. For instance, if your password was "manager" and SID was "orcl", please enter manager@orcl. This @<SID> tell SharePlex to connect via SQLNet, similar to what you would do for SQLPLus.
3. For the rest of ora_setup, please enter as usual. The user (using @<SID>) and tablespace must be the same as the current install of SPLEX user.
4. Once completed the ora_setup, please start sp_cop and resume as normal.