For 32bit dlls Widows 7 64bit have another REGSVR32.

regsvr32 for 32bit DLL in Win7 64bit place in this directory: C:\Windows\SysWOW64\

So just open cmd and do this: C:\Windows\SysWOW64\regsvr32  *.dll 

Where * – your 32bit dll also have placed in C:\Windows\SysWOW64\  of course if you need place it in windows dlls dir for 32bit dlls.