Tikisheet has been improved on 1.10cvs (but not backported to 1.9). However, you should use import & export in csv format, not on excel's, which doesn't work at all (even on 1.10). But with cvs, and OOo, it should work fine with OOo, even in Tiki 1.9.x.
I hope this helps...
Xavi ("TikiSheet" fan, specially when sheets are small).