NOTE: While I work with SRS, I do not work with SAP applications nor the 'sapinst' program/module/thingy, so fwiw ...
If there are problems with the repagent then three normal places to check for issues ...
After issuing 'sp_start_rep_agent master' ...
1 - do you receive any messages in your client/console?
2 - do any messages show up in the dataserver (ASE) errorlog?
3 - do any messages show up in the repserver (SRS) errorlog?