求助：Amos无法分析-经管之家官网！

初用Amos软件，诸多不熟练不熟悉。
中介效应分析：
按照吴明隆的书中所述，一步步画好模型图之后，导入数据分析运行模型。
然后，跳出出错提示框。 无法运算结果。
提示框内容众多，具体如下：
An error occurred while attempting to fit the model.
The sample moment matrix is not positive definite. It could fail to be positive definite for any of the following reasons：
1. The sample covariance matrix or the sample correlation matrix contains a data entry error.
2. The observed variables are linearly dependent（perhaps because the sample size is too small）.
3. The sample covariance matrix or sample correlation matrix was computed from incomplete data using the method of “pairwise deletion”.
4. The sample correlation matrix contains correlation coefficients other than product moment correlations（such as tetrachoric correlations）.
For maximum likelihood estimation only，it may be appropriate to check“allow non-positive definite sample covariance matrices”in the “Analysis Properties”window，or to use the Nonpositive method.
数据样本 来自spss数据
样本大小：1500
用spss已作出不完全中介效应。
这个提示说的主要问题，是数据不是正态分布么？（心里别说我小白啊小白啊小白啊……）
有什么方法可以解决呢？ 还是说……不能用Amos？
真心诚意虽不是十万火急但还是挺着急地向各位请教~~~