That was the laundering money case. Lu believed the prosecution's case for money laundering, that's why she was shocked. However, CSB was found innocent, so Lu was shocked for no good reason.
Basically the law states political donations belong to the politicians. During elections, KMT politicians get their campaign funds from the party. On the contrary, since DPP is really poor, politicians get their campaign funds mainly from small donors and heads of corporations. So DPP politicians with leftover political donations would fund small DPP candidates without funding. In the 8 years that CSB was president, Chen himself funded the DPP with 1,300,000,000 NTD for DPP candidates. He saved some of the money overseas as funds to establish the Taiwan nation.
Now if what Chen did was illegal or immoral, the legislative yuan should have changed the regulations on political donations, especially since for the past 6 years, KMT had control of the entire government. They have not. The current regulations on political donations, which only allows donations during election periods and puts a cap on max sum, became active in 2004, while CSB was the president and DPP had a good numbers of seats in the legislative yuan. Also, since then, KMT legislators have blocked DPP's calls for reform over 200 times.
Things to read about the persecution of Chen:
news.ltn.com.tw/news/politics/br ... ws/1181903
southnews.com.tw/specil_coul ... 2/0624.htm
liruhome.blogspot.tw/2012/08/201 ... _6881.html