[Eric] Error when opening existing projects with Eric 5.1

[Stjujsckij Nickolaj]

  When I try to open existing Eric projects (saved with Eric 5.0.x) with  
Eric 5.1.0, I catch the following exception:

XML parse error in file /home/sterkrig/dev/gruquotes/Gentoo.Ru  
quotes.e4pz, line 1, column 1
Error: Encountered incorrectly encoded content.

It occurs on both my Gentoo systems, including this one:

Python   3.2 (the same with 3.1)
Qt          4.7.2
PyQt      4.8.3
sip         4.12.1
QScintilla   2.4.6
WebKit   533.3
eric5      5.1.0 (rev 49fd4a2fe213)