求大神指导

小弟学protel 99se没多久，想试着画个stc51的实验板，现在遇到了好多问题，希望大神不吝赐教。
1。层次电路设计过程应该注意什么问题？
2. 元器件的封装和一些需要自制的元器件自制时应该注意什么问题？
3.下面是我画这个板子电器检查时出现的错误，为什么会有这样的错误？
#1 Error   Duplicate Sheet Numbers 0 MCU.Sch And Sheet1.Sch
#2 Error   Duplicate Sheet Numbers 0 MCU.Sch And Sheet2.Sch
#3 Error   Duplicate Sheet Numbers 0 MCU.Sch And Sheet3.Sch
#4 Error   Duplicate Sheet Numbers 0 MCU.Sch And Sheet4.Sch
#5 Error   Duplicate Sheet Numbers 0 MCU.Sch And Sheet5.Sch
#6 Error   Duplicate Sheet Numbers 0 MCU.Sch And Sheet6.Sch
#7 Error   Duplicate Sheet Numbers 0 MCU.Sch And Sheet7.Sch
#8 Error   Duplicate Sheet Numbers 0 MCU.Sch And Sheet8.Sch
#9 Error   Duplicate Sheet Numbers 0 MCU.Sch And Sheet9.Sch
#10 Error   Duplicate Sheet Numbers 0 MCU.Sch And Sheet10.Sch
#11 Error   Duplicate Sheet Numbers 0 Sheet1.Sch And Sheet2.Sch
#12 Error   Duplicate Sheet Numbers 0 Sheet1.Sch And Sheet3.Sch
#13 Error   Duplicate Sheet Numbers 0 Sheet1.Sch And Sheet4.Sch
#14 Error   Duplicate Sheet Numbers 0 Sheet1.Sch And Sheet5.Sch
#15 Error   Duplicate Sheet Numbers 0 Sheet1.Sch And Sheet6.Sch
#16 Error   Duplicate Sheet Numbers 0 Sheet1.Sch And Sheet7.Sch
#17 Error   Duplicate Sheet Numbers 0 Sheet1.Sch And Sheet8.Sch
#18 Error   Duplicate Sheet Numbers 0 Sheet1.Sch And Sheet9.Sch
#19 Error   Duplicate Sheet Numbers 0 Sheet1.Sch And Sheet10.Sch
#20 Error   Duplicate Sheet Numbers 0 Sheet2.Sch And Sheet3.Sch
#21 Error   Duplicate Sheet Numbers 0 Sheet2.Sch And Sheet4.Sch
#22 Error   Duplicate Sheet Numbers 0 Sheet2.Sch And Sheet5.Sch
#23 Error   Duplicate Sheet Numbers 0 Sheet2.Sch And Sheet6.Sch
#24 Error   Duplicate Sheet Numbers 0 Sheet2.Sch And Sheet7.Sch
#25 Error   Duplicate Sheet Numbers 0 Sheet2.Sch And Sheet8.Sch
#26 Error   Duplicate Sheet Numbers 0 Sheet2.Sch And Sheet9.Sch
#27 Error   Duplicate Sheet Numbers 0 Sheet2.Sch And Sheet10.Sch
#28 Error   Duplicate Sheet Numbers 0 Sheet3.Sch And Sheet4.Sch
#29 Error   Duplicate Sheet Numbers 0 Sheet3.Sch And Sheet5.Sch
#30 Error   Duplicate Sheet Numbers 0 Sheet3.Sch And Sheet6.Sch
#31 Error   Duplicate Sheet Numbers 0 Sheet3.Sch And Sheet7.Sch
#32 Error   Duplicate Sheet Numbers 0 Sheet3.Sch And Sheet8.Sch
#33 Error   Duplicate Sheet Numbers 0 Sheet3.Sch And Sheet9.Sch
#34 Error   Duplicate Sheet Numbers 0 Sheet3.Sch And Sheet10.Sch
#35 Error   Duplicate Sheet Numbers 0 Sheet4.Sch And Sheet5.Sch
#36 Error   Duplicate Sheet Numbers 0 Sheet4.Sch And Sheet6.Sch
#37 Error   Duplicate Sheet Numbers 0 Sheet4.Sch And Sheet7.Sch
#38 Error   Duplicate Sheet Numbers 0 Sheet4.Sch And Sheet8.Sch
#39 Error   Duplicate Sheet Numbers 0 Sheet4.Sch And Sheet9.Sch
#40 Error   Duplicate Sheet Numbers 0 Sheet4.Sch And Sheet10.Sch
#41 Error   Duplicate Sheet Numbers 0 Sheet5.Sch And Sheet6.Sch
#42 Error   Duplicate Sheet Numbers 0 Sheet5.Sch And Sheet7.Sch
#43 Error   Duplicate Sheet Numbers 0 Sheet5.Sch And Sheet8.Sch
#44 Error   Duplicate Sheet Numbers 0 Sheet5.Sch And Sheet9.Sch
#45 Error   Duplicate Sheet Numbers 0 Sheet5.Sch And Sheet10.Sch
#46 Error   Duplicate Sheet Numbers 0 Sheet6.Sch And Sheet7.Sch
#47 Error   Duplicate Sheet Numbers 0 Sheet6.Sch And Sheet8.Sch
#48 Error   Duplicate Sheet Numbers 0 Sheet6.Sch And Sheet9.Sch
#49 Error   Duplicate Sheet Numbers 0 Sheet6.Sch And Sheet10.Sch
#50 Error   Duplicate Sheet Numbers 0 Sheet7.Sch And Sheet8.Sch
#51 Error   Duplicate Sheet Numbers 0 Sheet7.Sch And Sheet9.Sch
#52 Error   Duplicate Sheet Numbers 0 Sheet7.Sch And Sheet10.Sch
#53 Error   Duplicate Sheet Numbers 0 Sheet8.Sch And Sheet9.Sch
#54 Error   Duplicate Sheet Numbers 0 Sheet8.Sch And Sheet10.Sch
#55 Error   Duplicate Sheet Numbers 0 Sheet9.Sch And Sheet10.Sch


这些是什么问题啊？还有就是有人说本科生画STC51电路板要求太高了，是不是真的要求太高了？
希望各位看到的都留下一点你们画板的经验，小弟感激涕零！！！！！！！！！！！！！！