Just installed and got it semi-working under Windows, I am a newbie and hope this helps.
1)Install EasyPHP-2.0b1 which has Apache, MySql, PHP all in one.

2)Unzipped i-doit_v09.zip to C:, rename directory from i-doit_v09 to idoit. (Or where/what ever you like, I like it @ root and short file name for sanity's sake.)

3)Create Alias under easpyphp, (make sure easy php is has started), applet e next to clock, right click on it, administration, under apache, click add, type in name idoit (or whatever), select patch c:\idoit (or whatever you have renamed the content directory to). and default settings, this is where you can allow/deny users. I didn't change anything here for now since I am doing testing, so I can only access on local machine.), OK.

4)Start browser of your choice (I used firefox), tyep in http://127.0.0.1/idoit/ or whatever you have alias the site to. This will bring you to the guided install menu. You should get an all OK. If not you have to go back and figure out which component didn't install properly.

Click Next, WWW directory = /idoit/ (or whatever your path is), Scroll down and select your choice of File, Temp and Object Image Directory. (I tried clicking on the file folder to browse but it filebrowser pops up with code so I just keyed in the path myself), so c:\idoit\file, c:\idoit\temp; c:\idoit\images (I created the file directory, temp and image already there)

Click Next, setup Database mysql. mySQL Client = C:\PROGRA~1\EASYPH~1.0B1\mysql\bin\mysql.exe. Use short file path, there is a bug if you put spaces in your path. Leave username/password for both i-doIT and root as is (I think I might have type in i-doIT/i-doIT and left root then password/blank). Default root password for easyphp mysql root account is root/blank. System Database Name: idoit (or whatever you like), Mandate Database Name: idoit (I kept it the same, not sure what the difference is). Mandant title I used company name.

Click next, select any theme (only 2) and leave the rest unless you really need to setup proxy and web/soap for integration with other apps?? Not sure.

Click Next and it should install.

Hope this helps… will try to drop DB and install again to confirm.