I have just installed IDEA 10.5.2 Ultimate on Windows7 Enterprise 64, running with Java 1.6.0_26 64bit and it will not start.
No messages in the log file so I doctored the idea.bat file to use the idea64.exe.vmoptions file and ran from command line and got this:
C:\Program Files (x86)\JetBrains\IntelliJ IDEA 10.5.2\bin>idea64.bat
Error occurred during initialization of VM
Could not find agent library yjpagent on the library path, with error: Can't load IA 32-bit .dll on a AMD 64-bit platform
I have checked that the win64 dir contains a legitimate looking (size is tha same as 10.5.1 installation) dll.