Our very own Steve Bucci recently posted this great video that shows you how to collect the logs and information from your App-V environment. With almost any App-V support call we will ask you for this information but knowing where to find these logs will prove invaluable when troubleshooting any issue you might run into.
We also have some additional information on the App-V log files here:
KB931803 - Log options for SoftGrid Client 4.x
KB930871 - How to interpret the messages in the SoftGrid Virtual Application Server log
J.C. Hornbeck | System Center Knowledge Engineer