Well that is just it, their guide is misleading. Windows XP doesnt have the ability to work with or boot any newer versions of Windows. But the issue you are coming across is the fact that they dont specifically state that you need .NET 2.0, but they do say to update Windows. That particular update is included with that bunch of updates right after you install XP. Which is why you cant install EasyBCD. If you could have followed the guide to the exact letter, you wouldnt have the issues you are cause you would have had .NET 2.0 and created a BCD for yourself to dual boot with. But since you didnt update, like the guide said right before it mentioned anything about the use of EasyBCD. So you didnt follow it to a "T" cause you couldnt due to no internet access.
As far as the EasyBCD page, yes it says boot anything. But did you go to the
EasyBCD Documentation to view the System Requirements?
You will note that it does state that Microsoft .NET 2.0 is required for the software. I will get it fixed to say that it requires internet access as .NET is not included with the download, it will download and install automatically if the system has an internet connection. It does help to know what the system needs for the software to run instead of just thinking that it will work without anything. We do have it shown and the links there for people to follow to get to the Documentation on what is needed. You just didnt do it. We really cant help you not reading the information available.
So you will have to do the same exact trick you did to get EasyBCD. Download the .NET 2.0 files, put them on a thumb drive and transfer them to the system. Then again, you could always just download the network drivers on the other PC, put them on the thumb drive and from there put those on the Thinkpad. Then you could access the internet and update XP as well as get the dual boot working.
Most likely, you wiped out the Recovery Partition. Either that or it was hidden and since it is for Windows 7 and not XP, you cant access it via the XP bootloader. Only via the Windows 7 Bootloader that you just wiped out.
So there is still another way. So try these new suggestions to get the software needed for .NET 2.0 or the drivers to the machine to complete the process for the guide.