virtual memory exhausted

[L]

I'm installing Kolab server 2.3.4 from source in a virtual machine with 
2GB RAM and the installation abort with this errors:

virtual memory exhausted: Cannot allocate memory
virtual memory exhausted: Cannot allocate memory
virtual memory exhausted: Cannot allocate memory
make[5]: *** [StrongPHIElimination.lo] Error 1
make[5]: *** Waiting for unfinished jobs....
make[5]: *** [SimpleRegisterCoalescing.lo] Error 1
make[5]: *** [SplitKit.lo] Error 1
make[4]: *** [all] Error 2
make[3]: *** [all-recursive] Error 1
make[2]: *** [all] Error 2
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2
error: Bad exit status from /kolab/RPM/TMP/rpm-tmp.48341 (%build)

What's the problem?
Thank.