Flash CFI in SoPC Builder

Yes ! you were right.

You use SOPC. which version of quartus do you use ? version 10 and 11 are transitions from SOPC to QSYS

I reopen an old project on Quartus II v9.0 wich is similar,

change the Data with to 8, 16, 32

I get no error like you :-/ (just overlap error for 32 bit width data)

It is strange that in your tristate bridge allow you do NOT share the "data" bus ; since data are always shared !?!

Have you build your SOPC yourself, or have you modified an existant SOPC ?

You are not alone : http://www.alteraforum.com/forum/showthread.php?t=43230&p=178794#post178794 (not resolved here)

Tristate bridge in QSYS (new SOPC from Quartus) is more difficult, but possible.

hard to help you, Good luck !