workbench 模态分析出错怎么解决啊？

错误信息：Eigenvalue extraction failed since the allocated storage for            
eigenvalues was exceeded.  This occurred while searching for converged  
eigenvalues either within a specified range or about a center value    
with a begin frequency of FREQB= 0.  Changing the beginning and/or end  
frequency values on the MODOPT command may help avoid this error. 

怎么解决呀