I have two questions:
1) Have you ever used the old installer (1.0.1) before, or have you only used the latest (1.0.9g/h) installer?
2) Which options did you choose while installing WoL? Did you choose to install it on a new folder or over your AoE3 installation?
3) Are you running a 64-bit version of Windows or a 32-bit one?