1. when i am going to change parameters there are some parameters thats already exist in configtool.i append the new parameters from this note to the existing parameters.Can i replace all parameters with the parameters in this note.
You just need to add the parameters in the config tool... Just append the parameters available in the note .
2. can i delete the logs before re-running the installer so that new logs and errors are clear.
Don't delete any logs... Logs will be appended... If you still wish, just rename the file. That will be enough.
Try to start the system manually after changing the parameter and check whether system comes online or not.
If not, please attach the latest updated dev_server0 log for more analysis.