在AMOS运行中，出现如下情况，应该怎么解决啊！
An error occurred while attempting to fit the model.
Amos couldn't find the inverse of the weight matrix for adf estimation. The observed variables in your model may be linearly independent, or the sample size may be too small.我有31个变量，样本量是400个。应该不是样本不够的问题。