HELP! An Unexpected error occurred while trying to install

Hello guys I am suddenly getting an error message. Here is exactly what happened.
I have always used ISBOXER perfectly without any problems, in fact I been using it all week. I would select the team I want loaded and it would load all the multiboxes without problems. However, this time I will start my character set as usual. The first box for character 1 will come up just fine, then when the second screen comes up to load character 2, I get an error message saying "An Unexpected error occurred while trying to install. Please try again or contact customer support." I don't understand because I have even updated the patches on diablo 3, and even the patcher for innerspace, etc. Here is the screenshot of what is showing on my screen. (the first box loads fine, then second box brings the error message) -------> http://tinypic.com/r/29b1q3c/5

Its been working all year without problems, this just started happening today. Please help me someone. How do I fix this???

Please reply asap!!!!

Its still happening guys, and I haven't gotten a solution yet. The only box that is loading is the very first one, but then when the second box opens Im getting that error message. PLEASE HELP! II want to go back to multiboxing.....

[lax]

Weird. I would try deleting your Diablo 3 Cache-2 folder (the cache folder for the Slot not launching) and allow ISBoxer to re-create it. That's C:\Program Files (x86)\Diablo III\Data_D3\PC\MPQs\Cache-2 if D3 is installed under Program Files (x86)

If you use multiple D3 installs for some reason, I might try launching the second folder launcher manually and see if that helps.

Lastly, you can just skip the launcher... http://isboxer.com/wiki/D3:Quick_Start_Guide#Part_1:_Before_configuring_ISBoxer -- after you have the "Skip Launcher" profile just go to each Character in the top left pane, then in the bottom right pane adjust the "Game" and "Game Profile" to whatever one launches the client directly instead of the launcher.

Lax, Thanks for your advice. It worked. Yes I have already tried launching the slot individually and that wasn't working. And I also think I have launchers off as well. However, I deleted the cache as you suggested and it worked like a charm. Thanks so much! now I can return to 4x drops!