The .NET agent logs can be found only in the common application folder (Usually under C:\ProgramData\ from Vista onwards and C:\Documents and Settings\All Users\Application Data\ for Windows Server 2003. This is a hidden folder)
Check the below folder path:
For Agent v2.3 and above:
\DotNetAgent\AgentLogs\
For Agent below v2.3:
For 64 bit: \DotNetAgent\x64\AgentLogs\
For 32 bit: \DotNetAgent\x86\AgentLogs\