Problemes with the playmode

Hello evryone,
First of all I would like to apologise for my english, ( I’m a french speaking).
I’m also sorry if it’s not the right place for my post.
My probleme is as follows:
I have just downloaded Unity 3.4.0 free version and when I want to use playmode I get the following message:
" All compilers errors have to be fixed befor you can use playmode."
What can I do to use the mode.
Os: windows 7

Many thinks in advance

you must fix the errors in your code.

Open the console (ctrl-alt-c or from windows menu) and fix all the errors it reports

Hi Dreamora,
Thanks a lot for your quick response. The console gives me the following message: " Assets/Scripts/UnderwaterEffects.js(23, 46):BCE0022: cannot convert ‘UnityEngine.GameObject’ to float".
I am a newby on programming so I don’t know what to do to resolve this probleme.
P.S: I have used Unity version 3.1 before but I have never met this kind of probleme.
You help will be appreciated.

the island demo is not unity 3 compatbile. you should use one of the unity 3 example projects until you get a hang of how unity works, that would be the bootcamp or the AngryBot

I have downloaded another copy of the software after deleted the first one. But during the installation I got the following message:" Problem executing: C:\Program files(x86)\Unity\Editor\Unity.exe: 1460 "
Do you have an idea what that means?
Thanks

Window 7 is really eating the source of my PC and I can’t run my game properly in it.