[BioC] Error in ebayes: No residual degrees of freedom in linear model fits

[Lucas Santana dos Santos]

Dear Group,

I am trying to find differential expressed genes using Limma, however  
I got the following error when I try eBayes:

Error in ebayes(fit = fit, proportion = proportion, stdev.coef.lim =  
stdev.coef.lim) :
No residual degrees of freedom in linear model fits

My dataset consists of 8 arrays from 8 different cell lines.  I have  
no replicates.
I just want to see which genes are differentially expressed between  
these cell lines.

I am wondering if I need more than one array per cell line in order to  
make this work.
Maybe eBayes need replicates to generate variability. Does it make  
sense?

A similar post already exists: https://stat.ethz.ch/pipermail/bioconductor/2005-May/009027.html

Thank you,

Lucas