Cyclone IV: GXB PLL atom can not be placed

[Altera_Forum]

I have 2 SFP connectors connected to a Cyclone IV FPGA. Previously 1 SFP was used with Ethernet and the other 1 was used with Optical link. We have two reference clocks, they are both 125 MHz. 

The Altgx modules were generated for the SFP connectors (Ethernet, Optical link). One Altgx module is driven by REFCLK1, the other is driven by REFCLK2. Everything works well with this settings.  Now I need to transpose the SFP-s, like the SFP previously was Ethernet, it should be Optical link now and etc.. So I tried to transpose the pins. First I transposed also the Reference clocks, than I left them like it was before.  And in both cases I get this error message from the Fitter:  error (167008): one or more transceiver atoms cannot be placed  error (167045): can't place gxb pll atom "optical_link_top_fortest:con_optical_link_top|altgx_ch0:altgx_opt_i|altgx_ch0_alt_c3gxb:altgx_ch0_alt_c3gxb_component|altpll:pll0|altpll_4j81:auto_generated|pll1"  error (167045): can't place gxb pll atom "optical_link_top_fortest:con_optical_link_top|altgx_ch1:altgx_eth_i|altgx_ch1_alt_c3gxb:altgx_ch1_alt_c3gxb_component|altpll:pll0|altpll_cd81:auto_generated|pll1"  Could someone help me, what could be the problem?http://www.alteraforum.com/forum/attachment.php?attachmentid=12893&stc=1