First is to check if your Sage 300 installed directory should have a A4wSingonMgr.exe under Runtime directory, if you don't have it, then you may need to install the System manger feature. The second possiblilty is that you did not run database setup to setup your system and company database.  If you have done both, then try to run REGACC.exe in the runtime folder as administrator to see if that helps.

A good reading for installation and administration is the Sage 300 Installation & Administration Guides.

Hi Terry, i have double checked the above and they are all set yet i still encounter the same  problem

I presume the Sage 300 installation is correct, the next action is to make sure Database you try to login is correct. you can use database setup program to create SAMSYS and SAMLTD database and use database load utility to load the sample database, this will tell you if your Sage 300 program is install properly and able to connect to sample database. You can also try to start Sage 300 as an administrator to see if it is a permission issue. 

If all are still not helping, you should contact Sage 300 support so they can help you as this is taking too long.