qmake: "error(message) requires one argument"

I'm working on Ubuntu 12.04, qt 4.8.1, qtcreator 2.8.1 (installed using ppa) and getting this error in a .pro file.

"error(message) requires one argument"

the line of code is:
error(updaterev not found, build tools first)

But if I write, for example:
error(ciao)

I get the error:
ciao

Attachment 9800

I don't understand how to fix it.

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Added after 30 minutes:

Ok, I'm stupid :cool:
The error is thrown by the error function.
Please ignore it.