Some of us had some troubles with our MT4. Here is a good article that addresses this issue. If you have a problem or when you're going to update your MT4 reading this article may help.
cheers
Where can I find my EAs, indicators, etc. on MT4 Build 600?
The latest version of FXCM MetaTrader 4 now saves your expert advisors, indicators, profiles, etc. in a different location on your computer. If you do not see your EAs and indicators in the navigator folder, your MT4 files are most likely still saved in the old folder location and are not recognized by the new version build of MT4.
Please follow the instructions below to move your files to the correct directory on build 600 of MT4.
1. First, find where you have your MT4 files saved currently. Below are the file types and location where these files may be currently saved on your computer. You may also want to check your desktop or downloads folders to see if you have copies of these files saved there.
2. Open MT4 > click on File > Open data folder > then double click the MQL4 folder. This will show you where your experts, indicators, etc. should be saved on your computer. Unless you have UAC settings disabled the folder location will be C:\Users\[user name]\AppData\Roaming\MetaQuotes\Terminal\[32 character long MT4 ID]\MQL4

3. Copy the files from the old location to the new location. For your EA's, for example, you will copy the contents of the C:\Program Files (x86)\FXCM MetaTrader 4\experts folder to C:\Users\[user name]\AppData\Roaming\MetaQuotes\Terminal\[32 character long MT4 ID]\MQL4\Experts

How to Recompile EAs and Indicators on MT4 Build 600
MetaEditor has changed in MT4 build 600 and as a result some expert advisors and indicators may have to be recompiled. Please follow the steps below to recompile your experts and indicators.
1. Open MT4 > go to File > Open data folder > double click on the MQL4 folder
2. Double click on the name of the expert advisor or indicator to open the file in MetaEditor.

3. If there are any errors when compiling the expert or indicator you will see those appear at the bottom of MetaEditor. You will need to address these errors before you are able to add the expert or indicator onto an MT4 chart.

for further information visit this website... http://www.dailyfx.com/forex_forum/fxcm ... ost1850261
thanks to him for putting it up!