I'm trying and failing to use SageTex

I've added the following code to a tex document: \usepackage{sagetex}

[ \sage{2+2}. ]

and then run PDFLaTex, and indeed I get the warning: Run Sage on "Filename".sage, and then run LaTeX on "Filename".tex again

I have sagetex-2.2.5 in the installed folder of the spkg folder of my sage installation and I have sagetex.sty in my Documents folder, but when I type: run "/root/Documents/Filename.sage" into a sage terminal I get the following error message. What's wrong?

Processing Sage code for "Filename".tex...

**** Error in Sage code on line 38 of "Filename".tex! Traceback follows.
Traceback (most recent call last):
File "/root/Documents/Filename.sage", line 12, in <module>
_st_.inline(0, latex(2+2))
NameError: name 'latex' is not defined

**** Running Sage on "Filename".sage failed! Fix "Filename".tex and try again.

SystemExit Traceback (most recent call last)

/root/Documents/Filename.sage in <module>() 12 _st_.inline(0, latex(2+2)) 13 except: ---> 14 _st_.goboom(38) 15 _st_.endofdoc() 16

/home/dcomerf/sage/local/lib/python2.6/site-packages/sagetex.py in goboom(self, line) 169 self.souttmp.close() 170 os.remove(self.filename + '.sout.tmp') --> 171 sys.exit(int(1)) 172 def endofdoc(self): 173 sagef = open(self.filename + '.sage', 'r')

SystemExit: 1 WARNING: Failure executing file: </root>